Power Risers/Fallers for Week 20: Buy or Sell?

RotoBaller's Premium Power Surgers tool helps you identify home run risers and fallers to see who is worth adding or streaming In Week 20 of the 2018 fantasy baseball season.

Welcome to Week 20 of the 2018 MLB season and a new week of our investigation into the steepest power trenders in baseball, whether those trends are positive or negative.

As the season has blown by into August and the MLB trade deadline has passed, the window of opportunity to snag a surging slugger or to rid yourself of a down-and-out disappointment grows shorter with every plate appearance. Most Fantasy Baseball Leagues have already had their trade deadlines come and go, and the only decisions left for Managers to make in terms of personnel are whether players are worth the AB they are receiving and whether a player is worth adding for a postseason push. Getting the jump on identifying the catalytic variables and telling trends in these player's recent offensive performances could be the key factor in the management of your roster in the season's final months.

To do this, we'll be taking a look at the batting metrics that influence a hitter's power (Fly-Ball%, Pull%, Hard-Hit%, Exit Velocity) and determining whether you should buy or sell respectively on these surgers and strugglers. Since it's always best to wait and trudge through with the power play from players like Bryce Harper, Charlie Blackmon, Joey Votto, and Mookie Betts, we are going to be focusing on players who have seen a change in their power profile due to a change in batting metrics and has either warranted greater attention for waiver wire pickups or for a potential trade to cash in on what's left before it's too late.

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Power Risers

Ronald Acuna Jr. - (OF, ATL)

The heat levels go: mild, hot, blazing, ghost pepper, and then somewhere a little further down the line is where Ronald Acuna sits with his recent offensive performances. Within a span of just the last seven games he has clobbered seven HR with an amazing slash line of .483/.531/1.276 to give him 19 HR and a .992 OPS in 264 total AB this season. Though he strikes out a lot at 28%, that is about all that there is to complain about. He has powered his way to a .288 ISO this year off of 44.6% hard contact and just 12.5% soft contact on batted balls, and gave himself further opportunity to send pitches yard by hitting 40.8% fly balls with a pull rate of 45.1%. Overall, with a 90.8 mph average exit velocity and average HR distance of 413, Acuna's HR/FB ratio is an impressive 25.3%.

Ronald Acuna is just 20 years old and was baseball's top prospect as recently as pre-2018. With his August hard contact rate of 54.8% translating to an ISO of .518, he jumped into the history books this week when he became one of two players in the modern era to hit three straight lead-off homers. Whether it has been the minors, majors, or professional baseball in Australia, there has yet to be a place where Acuna has failed to demolish opposing pitchers. He is going to make the race with Juan Soto for National League Rookie of the Year a photo finish, and while there still may be a few questions lingering with some of his young Atlanta teammates, consistent offensive dominance like this is starting to make Ronald Acuna look like a perennial freight train for a contending club.

Freddy Galvis - (SS, SD)

At 28 years old, Freddy Galvis has never even had a season with an OPS north of .690. Most of this season has been well in line with that standard, with monthly OPS between .611 and .664 from April through July. This, however, hasn't stopped him from going on a tear in August. In 46 AB this month Galvis has a .261/.320/.630 slash line and five HR, including a torrid stretch of three straight games with a dinger from August 12th through August 14th. Is this recent stretch an indicator that he could be a sleepy option for Fantasy Baseball Managers down the home stretch who need power at shortstop?

Galvis sports a few underwhelming peripherals. His ISO of .129 is far from intimidating while his strikeout rate of 22.5% is higher than ideal. Also, his GB/FB ratio leaves a little to be desired at 1.24, and his average exit velocity (88.4 mph) and HR distance (390) sit below the league norm and aren't giving him that much-needed assist in pitcher-friendly Petco Park. He, however, counters with several equally positive signs. His walk rate of 7.4% is the highest of his career, and though his pull rate is 38.9%, he has strung together two consecutively better months in that department with July and August rates of 40% and 47.1%. His worst two months in terms of GB/FB tendencies came in the first two months of the season, and since then he has mightily improved and is even hitting fly balls at a 42.4% clip this month. He has produced solid cumulative hard and soft contact rates on batted balls this season of 38.9% and 13.9% though, confusingly, he has produced his lowest hard contact rate of the year (32.4%) in this, his breakout month of August in which he produced his highest ISO of the year (.370) by a substantial margin of .226. Part of this mystery can likely be explained by the fact that Galvis has improved his pull rate so substantially and the fact that he has been able to produce most of his hard and medium contact on batted balls that turned into line drives and fly balls. The Padres have put Freddy Galvis on the field for every single game of the year so far, so it's fair to say that he'll receive ample opportunity moving forward. Though his home field and career history leave some lingering doubts, he could be a Marcus Semien type fill-in shortstop for Fantasy Baseball Managers willing to sacrifice well-roundness and consistency for a sneaky power/speed combo.

Marwin Gonzalez - (SS/1B/2B/OF, HOU)

With the exception of a good sum of work in June, Marwin Gonzalez has been a far cry from the 23 HR, .907 OPS utility man that was the x-factor on a World Series squad and finished 19th in MVP voting. However, things have been looking up in a big way for Gonzalez since the beginning of August, and he has hit four dingers with a slash line of .349/.417/.674 in 46 AB during that stretch. Some of his peripherals have remained rather consistent all season. His plate discipline figures and pull rate have all remained in the same neighborhood from month to month, and his cumulative walk rate, strikeout rate, and pull rate sit at 10%, 23.9%, and 43.6% respectively. Other figures have fluctuated a little more than one likes to see. His GB/FB ratio bounced around from 0.93 to all the way up to 1.87 between April through July before reaching his best mark of 0.83 so far in August off of a combined 67.7% fly balls and line drives.

His batted ball contact has also been up and down. Between April through June he had produced hard contact rates between 23.5% and 45.6% as well as soft contact from 14.5% to 21.6%. This is consistent with his simultaneously fluctuating ISO that ranged between .063 and .211 in that time span. Since the start of August, he has been producing a season-best hard contact rate of 50% on batted balls, which has subsequently given him his best monthly ISO of 2018 at .326, even though his soft contact rate for the month is currently still high at 18.8%. Even with some figures that sit below league average like average exit velocity (88.3 mph) and HR distance (390 feet) Marwin Gonzalez, when at his best, is a well-rounded player capable of a 20+ seasonal HR pace from month to month. Though consistency hasn't been his staple this season, that blow is cushioned a bit by the quadruple-position eligibility and the fact that he goes to work for one of baseball's most offensively devastating batting orders. Even with the regression from his 2017 season this year, his total hard contact rate for 2018 of 35.9% is a 3.2% improvement from last year while his soft contact rate of 18.3% is also a slight improvement by 0.3%, so maybe the greater aversion to grounders since the start of August will turn out to be the big difference maker.

Tim Beckham - (SS/3B, BAL)

Former highly touted prospect Tim Beckham, like Marwin Gonzalez, is experiencing a hangover from a breakout 2017 campaign that saw him hit 22 bombs with a .782 OPS. He played only five games in July for the bottom-dwelling Orioles, but his months of April and July were ugly. In 84 April AB he managed just one HR and a meager .509 OPS, and in 100 July AB he struck three long balls and sauntered to a .699 OPS. Though these figures are unimpressive, they show one optimistic trait: they demonstrated improvement from month to month, a theme which Beckham continued into August. This month he has already hit four homers with an OPS of .828 and an ISO of .280 off of 34.3% hard contact, all being season-bests.

The numbers still support airing heavy on the side of caution when it comes to trusting Tim Beckham. This month he has also produced his highest soft contact rate of the month at a discouraging clip of 28.6%, while his cumulative soft contact on the year of 23.6% isn't a whole lot better. His walk rate (7.2%) and pull rate (43.4%) are good, and his GB/FB ratio has seen some steady improvement, but his strikeout rate is still very high at 26.6% and even with the improvement his GB/FB ratio for August has only descended as low as 1.25. Even with such a low exit velocity of 86.9 mph, he clearly possesses some raw power as evidenced by his average dinger distance of 404 feet. He does not, however, apply consistent enough high-quality contact to batted balls or present enough of a well-rounded game to Fantasy Baseball Managers as can be seen from his low BA/OBP and lack of stolen base attempts after at least grabbing six swipes last season. Infield offense can be found elsewhere at this point in the year without having to make such a roll of the proverbial dice.

Power Fallers

A.J. Pollock- (OF, ARI)

Though A.J. Pollock to this point is turning in one of his best offensive campaigns yet (maybe even his best), close examination of a few of his posted figures could cause a little anxiety. Namely, several key figures have been on a steady downward trend since the start of the year. His OPS went from 1.021 in April, to .857 in a May cut short by injury, to .836 in July after missing the entirety of June. Now in August, he has struggled to a .243/.300/.270 slash and zero HR after hitting 15 homers in the previous 134 AB. This caliber of performance at the plate has carried with it the baggage of a steadily decreasing HR/FB ratio as well as ISO.

Thankfully, a vast portion of his recent ugly stretch can be explained by just a couple of factors. For one, he has started off August striking out at a stratospheric 35%, which although rather concerning of a figure, it is a stark outlier in terms of Pollock's career tendencies. Also, after keeping his GB/FB ratio under control for most of the season leading up to August, this month his ratio has ballooned all the way up to 3.50 off of 60.9% grounders and just 17.4% taking flight. These figures of stark contrast to Pollock's career norm in what has otherwise been a very successful yet injury-shaken year seem to indicate that he could bounce out of this rut in the blink of an eye. His cumulative pull rate of 49.8% is fantastic, while he has produced hard contact rates between 42.3% and 52.8% every month and solid figures between 8.7% and 15.3% each month in terms of soft contact. His 20-15 power/speed potential may be hampered a bit by the fact that he has taken just one bag of his ten on the season since the start of July, but his exit velocity (90.2 mph) and average HR distance (407 feet) in hitter-friendly Chase Field bode well moving forward. If A.J. Pollock can once again limit his strikeout and ground ball frequency, he could be a lit fuse for Fantasy Baseball Managers needing a spark in the little time of regular season action remaining.

Gorkys Hernandez - (OF, SF)

With a .738 OPS and 13 HR in 315 AB for San Francisco, Gorkys Hernandez is certainly having the best season of his career from many perspectives at the age of 30. Excluding 2016 in which he only took 54 AB, his 2018 ISO (.171), hard contact rate (40.5%), and GB/FB ratio (1.37) are all career bests and in fact drastic improvements from past performances. Besides that, his pull rate (35.3%), strikeout rate (25.5%), and soft contact rate (19%) remain inadequately high for the hitting conditions presented by AT&T Park. Just in this season, several things have plagued Hernandez in recent months. First, his monthly soft contact has increased every month from 14.3% in April to 28.6% so far in August. His GB/FB tendencies have been erratic, including three particularly dirty months with ratios of 1.72, 2.60, and 3.00 so far in August off of 71.4% grounders.

That seems to be what is mostly responsible for his current unsightly August slash of .172/.226/.207, a stretch for which he is homerless. Otherwise, Hernandez has been applying sturdy contact to batted balls. After the slow start he got off to in April, he has ranged from 36.8% to 45.3% in terms of hard contact, with a confusingly high rate of 57.1% for his struggling start to August. In addition, his heavily improved exit velocity of 88.5 mph is finally on pace with the rest of the league, while his 406-foot average distance on dingers indicate he possesses power worth of consideration. He has stepped up his power game this season in addition to grabbing five steals and has demonstrated an ability in the past to steal bases at a significantly greater frequency. Though his August soft contact rate and ground ball percentage have to decrease, and soon, for him to warrant taking a chance on. Those are two figures when combined together at high rates, do not project well for hitting balls into the stands.

Odubel Herrera - (OF, PHI)

Odubel Herrera has been one Philly not off to the races in the month of August. With a goose egg in the HR department and a slash of .176/.200/.235 over 34 AB, August is the lowest link in the chain of monthly OPS that have been steadily decreasing since he produced a figure of .905 in April. Several present peripherals make you want to walk on eggshells around Herrera. He has been striking out at a clip of 20.3% and seems to struggle with lowering his strikeout percentage in a month without also lowering his walk rate. This year, though his month by month figures have varied little; he sports stagnant batted ball contact figures of 24.9% hard contact, 28.6% soft contact, on 44.4% grounders. Though his pull rate (39.9%) and HR distance (398 feet) sit at league average, his exit velocity of 86.7 mph suggests that he just doesn't hit the ball very hard.

Yet, through all of this Odubel Herrera has clubbed a career-high 19 HR already with a .179 ISO which is also the best of his four-year tenure. The fact is, Odubel Herrera has always hit for low hard contact and high soft contact, and despite this managed to continue to improve his HR hitting capabilities. Has hard contact rate sits extremely low at 20.7% for August. To return to hitting HR on a five to seven per month pace, that will have to come up by around 8%. Though the figures are very low when compared to other prominent players, he has demonstrated an ability to hit HR at a nice pace on hard contact rates in the high 20% range. The former All-Star doesn't steal 15+ bases anymore, so he'll have to start doing this in addition to bringing back his usual well-rounded offensive play if he isn't going to cause damage to Fantasy Baseball Managers who choose to deploy him. This might have to be a group effort to get out of a slump on offense: the Phillies have scored the second-least runs in baseball since August began.

Kyle Schwarber - (OF, CHC)

Kyle Schwarber is another player who has been a regressing component on a regressing unit, as the Cubs have been the seventh-worst run-scoring offense in baseball since August started, and Schwarber owns a .219/.301/.329 slash and just two HR over the last 22 games. We discussed Kyle Schwarber all the way back in Week 7, so let's see what has changed for him since then. The only month in which he has had such offensive issues has been August where he currently holds his lowest ISO figure of the season at .107, but despite this, he has been producing 40.7% hard contact and 14.8% soft contact for the month on a GB ratio of 0.45. He still strikes out a lot (though not as often as 32.1% from July) and his usually high walk rate has dropped by more than 10% over the last two months. The two more telling factors may be his diminished pull rate of 33.3% and IFFB frequency of 27.3% that has led to his lowest HR/FB rate of the year of 9.1%.

If you ever need a reminder of Kyle Schwarbers Herculean strength, consult his Home Run Derby showing or feats like 470-foot bombs. Schwarber's current capabilities and limitations seem to be apparent, and with some erratic peripherals that directly impact HR hitting, some down times can be reasonably expected. Though these down times should remain infrequent. His proclivity for moon shots, the hitter-friendly confines of Wrigley Field, and his average exit velocity of 90.6 mph should be enough to power himself and partially the Cubs out of this slump soon. When the club as a whole recovers, streakiness aside, Schwarber's bat will be all the more valuable.

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