Power Risers/Fallers for Week 23: 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 23 of the 2018 fantasy baseball season.

Welcome to Week 23 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.

September has finally arrived, which means the homestretch of 2018 is upon us. 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

Hunter Dozier - (1B/3B, KC)

It's been a tale of two halves for former top-100 prospect Hunter Dozier. In 172 AB over the first half of the season, he was only able to accumulate four HR and a meager slash of .209/.269/.331, perfectly in rhythm with the Royals and their miserable year of 2018. However, something has clicked in a big way for Dozier in his 113 AB of the second half of the season as he has blasted his way to five homers already and a much-improved slash of .283/.322/.522. With his bat finally finding a home in the majors, how did he manage to turn things around and what can be expected from him through the rest of September?

Dozier has managed to improve his output in several key statistical categories over the latter half of the year. Though his walk rate went down by 2%, he was able to bring his strikeout rate down from 31.7% over the first half of the year to a more manageable 25.6% so far in the second half. Though he is producing 7.3% fewer fly balls, he has mustered more offense by creating 14.5% more line drives over the second half of the season, and his pull rate also improved from 38.9% to 43.4%. The most important thing for Hunter Dozier through 2018 has been his strength of contact. Even when he struggled over the first half of the year he still produced 44.3% hard contact and just 13.3% soft contact, and although he has hit for slightly more soft contact so far in the second half (14.5%) he has been churning out hard contact at an impressive clip of 48.2% on his way to an ISO of .239 to this point in the half. Dozier was enticing simply for his consistent quality of contact this year and figures that demonstrate his pop at the plate like his 90 mph exit velocity or 401-foot average distance on dingers. Now that he's matching his power with more all-around offense generated through hard-hit line drives, he could be a widely-available x-factor at the corner infield until October.

Jake Cave - (OF, MIN)

Jake Cave has been swinging for the fences, and sending pitches past them in the process. He has hit seven HR in 94 combined AB in August and September, and has produced four of those over the last eleven games along with an OPS of .870. Cave has achieved his recent red-hot run through reckless abandonment, and that doesn't come without serious reservations about his prospects for the rest of the season. Over the last two months he has been striking out at rates of 34.8% and 37.5%, and as could be expected, his BA and OBP have suffered considerably. He has nonetheless achieved smashing success in the power department to this point in September by applying 60% hard contact and a 60% pull rate to fly balls that he has been creating at a 40% clip.

Cave's production at the plate so far this month seems to characterize him as more of streaky phenomena than an emerging force. His average HR-distance of 418-feet is eye-popping, to say the least, and the fact that he has mixed improving hard contact with consistently-infrequent soft contact is very encouraging. Impressive as the 25-year-old has been lately, his numbers from September serve as a limited sample and are far outside the range of his normal operating capabilities. At his best at this point in his career he appears to be able to produce a month of good BA and OBP or a good month of power-hitting, but not both. He hasn't been stealing bases at the solid standard he set for himself in the minors, and his minor league track record seems to suggest his range for homers hit over a full season would be around 15-20 at his peak. It would be wise to remain skeptical of Jake Cave as the regular season winds down.

Luke Voit - (1B, NYY)

Luke Voit's prominence in pinstripes has been well documented. Since being acquired by New York for Chasen Shreve and Giovanny Gallegos, Voit has blasted into the Big Apple with an amazing seven homers and a slash of .322/.385/.678 in just 59 AB. Even the areas of offense that Voit has seemingly struggled with don't seem to carry much negative impact for him. Even though he strikes out at a high 29.5% clip, he supplements his plate discipline with an exceptional walk rate of 10.3%. His pull rate has been just 35% over his momentous second half, but it has hardly had an effect on his ability to knock balls into the stands at Yankee Stadium. He has produced well-rounded offense by hitting line drives at a 29.8% rate this year, and he started to hit HR at an improved pace once his frequency of fly balls hit 57.1% to this point in September.

In total, Luke Voit has posted a robust .343 ISO in 2018 off the back of 44.7% hard contact and just 12.8% soft contact that has failed to waiver in his limited run for the Yankees. His average exit velocity this year has been well north of the league norm at 92.1 mph, and his cumulative minor-league slash line of .288/.370/.459 suggests that this level of play is well within his personal capability. With his consistent high-quality contact for one of baseball's best batting orders (that plays in one of baseball's most hitter-friendly stadiums), Luke Voit is about to come up very clutch for the New York Yankees and fantasy baseball managers alike as October approaches.

Whit Merrifield - (2B/OF, KC)

Whit Merrifield may not top his 19 bombs from 2017, but he is still having an incredible campaign for the Royals in 2018 as he is still contending for the BA (.306) and SB (30) titles. Though he has had some trouble to kick off September, he recovered his power-touch nicely in August when he held a slash of .358/.413/.541 with five dingers in 109 AB, so is he poised to repeat his power-hitting pace of 2017 over the last few weeks of Kansas City's season?

Through his excellent batting average and on-base percentage, we know that Merrifield's issue on offense isn't his plate discipline and approach for accuracy. His batted-ball contact has been good also: he has produced hard contact at a 38% clip this season while he produces soft contact at an infrequent rate of 14.8%. His strength very well may be a significant obstacle because, despite his solid batted-ball contact, he has only managed an average exit velocity of 87.1 mph and has produced monthly ISO figures between .085 and .183. His pull rate of 35.7% is certainly less than ideal for power-hitting and though his GB/FB ratio of 0.92 typically bodes well for sending pitches deep, it's much more oriented to support his elite batting average since he produces 28.7% line drives and he lacks the raw strength to take great advantage of his 37% fly balls. Whit Merrifield could easily end the regular season with 14 or 15 knocks, and his peripherals certainly support his phenomenal season as legitimate, but they may also indicate that his 19 homers from 2017 may be his peak if he's going to contend for the BA and SB titles in the American League.

Power Fallers

Corey Dickerson - (OF, PIT)

During July, Corey Dickerson was nearly unstoppable on offense with six homers and a 1.253 OPS in 70 AB. Since then, however, things have gotten ugly for Dickerson with seemingly no light at the end of the tunnel. He has failed to hit even a single HR in 98 AB since July and has posted an unsightly slash of .185/.193/.222 over the last 28 days. So after his explosive month of July, what has been the cause of his dramatic downturn and is the end of this slump conceivably in sight? Since he has only taken part in two games so far in September, let's dive into his offensive figures from August to determine where exactly things went wrong.

It seems as that with all other factors isolated, the three peripherals that stand out in determining Dickerson's offensive success are pull rate, GB/FB ratio, and strikeout rate. He started striking out at a 23.4% rate in August (not to mention 37.5% to start September) which is his highest of the season for a full month of work. Also, his pull rate fell to an abysmal 27.1% during August after being as high as 39.7% during his hot run of July. The fact that this has contributed to his mediocre play is supported by the fact that his pull rate has continued to dive and sits at 20% thus far through September. Also, his GB/FB ratio rose to a season-high mark of 1.58 in August off of a lopsided 43.5% grounders and just 27.5% flyers, making it relatively difficult to hit homers at a consistent pace. Quality of contact, thankfully, doesn't appear to be a big part of Dickerson's issues. He hit for 35.7% hard contact and 18.6% soft contact in August, which despite the vastly different results is not a far cry from his respective rates of 44.4% and 15.9% in the heat of July. His HR-distance of 398-feet is right at league-average and his exit velocity of 87.4 mph is a full tick below, so there are limitations to his power-hitting ability, and with things taking a turn for the worse for Pittsburgh's offense ironically since they decided to make a push for the postseason, it's difficult to picture Corey Dickerson wrapping his game together for the final three weeks of the regular season.

Francisco Cervelli - (C, PIT)

As we said when we discussed Francisco Cervelli earlier in the season: he is no-doubt having the best offensive season of his career with a .825 OPS and eleven HR. However, his power-hitting has been minimal since the start of the year. In fact, Cervelli has failed to hit more than one HR in a month since he opened the year with two consecutive four-homer months. His batting average and on-base percentage have remained fantastic in months not hampered by injury but his power-hitting has taken significant steps back, as displayed by his most recent stagnant two-week stretch in which he produced a slash of .289/.357/.316 with zero HR to speak of.

It's always good news when the problem can at least be identified, and the issue for Cervelli's power-hitting potential seems to be the dramatic shift in his GB/FB tendencies from the first half to the second. He produced 35.4% grounders and 47.9% fly balls over the first half, but during the second half, he has seen vastly different respective figures of 41.1% and 32.9%, with nearly a 10% increase in line drive rate which helps support his BA and OBP through that time. Otherwise, his pull rate actually improved from the first half to the second half to 40.5%, and (not including limited AB in September) he has only had one month (July) in the season where his hard contact rate was below 34% and his soft contact rate was above 14%. His 89.2 mph exit velocity has been translating line drives into base hits, instead of fly balls into homers. He has failed to produce an ISO north of .154 since May and though there is nothing wrong with deploying a catcher with an unusually high BA and OBP, at this rate we may be looking at Francisco Cervelli's career-high season-HR total settling at eleven or twelve.

Yasmani Grandal - (C, LAD)

Power isn't Yasmani Grandal's problem. He has notched 22 dingers in 377 AB this season on his way to a .225 ISO and his exit velocity (89 mph) and HR-distance (403-feet) are both above league-average. Also while his soft contact rate has been consistently high all season and sits at 20.1%, he has produced 40.5% hard contact throughout the year with a very helpful pull rate of 47.4%. While he still hits for power, poor offensive execution will nonetheless hamper his ability to wrack up homers to the best of his ability. A big part of Grandal's issues has been his plate discipline. While he has built up his OBP with a fantastic walk percentage (13.3%), he has been striking out at a much faster clip including a month of August where he struck out 30.3% of the time (he is striking out at a 44.4% clip to start September).

Also, Grandal hits few line drives with a rate of 17.2%. So even though his GB/FB ratio is 0.99 off of 41.6% fly balls, that still leaves a 41.2% gap that is filled with grounders. In conjunction with his high-volume of soft contact, this means that a large portion of Grandal's batted-balls are significantly deterred from becoming either base hits or HR. His hard contact and fly ball rate ensure that he will continue to hit homers at a relatively regular pace, and his ability to draw frequent walks will put him on base for the top-ten Dodger offense to drive home. However, his proclivity for strikeouts with his GB/FB tendencies detract greatly from what he can accomplish in a given month and prevent him from being a well-rounded asset even at catcher.

Nick Markakis - (OF, ATL)

In his All-Star season, Nick Markakis has been one of the driving forces behind the Atlanta Braves offense with 14 HR in total with a .829 OPS. However, Markakis has struggled mightily since the end of July and over the last twelve games (46 AB) he has managed to knock zero dingers and has a less-than-pedestrian slash of .196/.288/.239. Unlike several players mentioned above, Markakis has hardly struggled with plate discipline over the course of the season.  He strikes out at a rate of just 11.2% while taking a walk in 9.7% of his opportunities. Really, his issue doesn't appear to be much of anything. He has produced 40.8% hard contact with just 13.2% soft contact, and he hits for a solid exit velocity of 90.6 mph. Despite this, he has managed just a .154 ISO on the season. This could be due to his fly ball rate of 31.6%, as he sustains his BA by hitting 27% line drives.

It is also worth noting that even though Markakis currently produces an already-low pull rate of 31%, his problems at the plate didn't really begin until his pull rate for August and September dipped down to 24.3% and 25%. He is very likely going to finish a season with 15+ bombs for the first time in seven years, and for that, he can thank the highest hard contact rate of his career (by a margin of 6%). His peripherals indicate that he should get back on track soon for the dangerous Braves batting order and when he does his well-rounded offensive approach will hold tremendous value. However, as far as power-hitting is concerned, taper expectations for HR-totals through the end of September and expect Nick Markakis to bash another two or three by the time the regular season has concluded.