Power Risers/Fallers for Week 24: 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 24 of the 2018 fantasy baseball season.

Welcome to Week 24 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

Brandon Lowe - (SS/2B/OF, TB)

After a Lowe-key entrance to the major leagues, Brandon Lowe has turned things around in a big way to start September and has made a powerful impression in the process. Over his last 56 AB for Tampa Bay he accrued a tremendous slash of .304/.418/.589 as well as four HR to boot. The 24-year-old former Maryland Terrapin has managed this level of September-slugging through improvements in several key peripheral categories.

Though he strikes out a lot with a rate of 26.9%, he counterbalances this by taking frequent walks with a rate of 14% and has also sported consistent pull-rate figures throughout his limited MLB experience with an overall figure of 44.4%. In August, Lowe produced a high GB/FB ratio of 2.13 off of just 25% fly balls and 53.1% grounders. Since then, he has nearly flipped these figures completely around with a 40.9% fly ball rate with just 27.3% ground balls, resulting in a much more power-friendly GB/FB ratio of 0.67. Also shifting significantly was Lowe's quality of contact. From August to September his hard contact rate jumped from 28.1% to 40.9% while his soft contact rate went from a stratospheric 28.1% to a dialed-in 9.1%. With his improved contact-quality paired with an above-average exit velocity of 89.6 mph, Lowe has produced a phenomenal ISO of .387 for September and HR figures that are well in line with his minor league track record. With his ability to produce a high proportion of line drives and fly balls mixed with strong contact-quality, Brandon Lowe is a well-rounded emergent bat out of the middle infield with power upside and the added bonus of being able to swipe a few bags.

Adrian Beltre - (3B, TEX)

Though he has had success in terms of BA and OBP this season (on his way to becoming the MLB's International hit-King), it hasn't been a big campaign in regards to power-hitting for Adrian Beltre this season, as he struggled immensely through July and August when he knocked just three dingers combined in 157 AB. However, like clockwork, the 39-year-old future Hall of Famer has recovered for a huge start to September for Texas with a fantastic five homers with a slash of .297/.366/.730 over just 37 AB. What is allowing him to finish his 21st MLB season so strongly?

Nearly every aspect of his game that provides an assist to power-hitting has been improved thus far into September. Beltre has brought his strikeout rate from 22.2% in August to 14.6% this month and has maintained a solid walk rate of 7.3%. His pull rate has been boosted up to 48.4% after being at an uncharacteristically-low 27.8% during August, while his GB/FB ratio went from 1.14 off of 44.4% grounders and 38.9% fly balls to a ratio of 0.33 this month from 58.1% fly balls and a meager 19.4% ground balls. Most dramatic are his shifts in batted-ball contact. His hard contact rate went from 37% to a substantial 54.8% while his soft contact rate went from an unusually-high 22.2% to a minimal 3.2% from August to September. All these statistical shifts have been a perfect storm brewing for Beltre to bash a bunch of bombs from now until the end of the regular season for a Rangers offense that ranks second-best in all of baseball since the All-Star break in terms of runs scored. 26 more dingers for Beltre until he reaches the monumental mark of 500, and with this kind of run down the final weeks of the season, he is giving himself a great chance to accomplish that next year by age 40...if he decides to continue playing.

Ji-Man Choi - (1B, TB)

Since joining Tampa Bay from the Milwaukee Brewers in exchange for Brad Miller, Ji-Man Choi has received a much greater share of playing time. He has made the most out of this increased opportunity for the Rays; he has improved at the plate every month since being added and that crescendo has so far culminated in an explosive month of September in which he Choi has smacked three homers with a 1.199 OPS in 30 AB. What aspects of his offensive approach have transformed the 27-year-old native of South Korea from an after-thought for the Brewers to a clutch force of nature for the Rays?

Initially, a big difference can be seen in his plate discipline from the first half of the season to the second. His strikeout and walk rates over the first half were extremely ugly at 44.2% and 4.7%, but since then he has produced much more balanced marks of 21% and 13%. So far in September, Choi has produced a solid GB/FB ratio of 1.00 with 43.5% fly balls after producing a rate of just 29.8% in August, and he is also putting up a robust pull rate of 60.9% as compared to an already-tolerable 39.6% from August. Like many other players putting together a strong September stretch, Choi can most attribute his recent success to the quality of contact on batted balls. Over the last two months, he has boasted hard contact rates of 47.9% and 43.5% respectively while his soft contact rates have been simultaneously stellar at 14.6% and 13%. This quality of contact along with well above-average peripherals for exit velocity (90.1 mph) and HR-distance (407-feet) allowed Ji-Man Choi to steadily improve his monthly ISO from .147 in July, to .206 and .433 through August and September. The Rays are currently the top run-scoring club in baseball so far in September, in no small part thanks to Choi, and he packs key value down the home-stretch as the rest of the Tampa Bay batting order heats up.

Adalberto Mondesi - (2B/SS, KC)

While he certainly can't hit homers like his father Raul, Adalberto Mondesi has nicely demonstrated his improving proclivity for power throughout the 2018 campaign. Over his last 64 AB "La Guinea" has knocked three of his seven dingers on the year while producing a slugging percentage of .469. The former highly-touted prospect didn't really start to show signs of power-potential until 2017 when he managed 13 HR for Triple-A Omaha, and now is starting to look like candidate for 15+ bombs if given a full season of work at shortstop in addition to the fact that he has already stolen 21 bases in just 196 AB all year. So what is different in 2018 from his first 188 AB for the Royals in 2016 and 2017 when he struggled mightily with the bat?

For one thing, while his strikeout rate of 26.2% is still high, it is down by more than 10% from last season. His pull rate has actually decreased but still sits at a solid 40.3% while his GB/FB ratio has decreased to 1.04 off of 38.8% fly balls and 40.3% ground balls. Mondesi's speed makes the greater volume of grounders a non-issue. With his GB/FB tendencies leaving room for 20.9% line drives, the more balanced distribution of his batted balls allows for him to achieve well-rounded offensive results and sustain his current BABIP of .341. Also, despite a high frequency of soft contact (20.8%, which is actually down 2.1% from 2017), Mondesi has demonstrated some surprising strength. His hard contact rate rose tremendously from 25.7% last year to 40.3% this season, and with above-average marks in terms of exit velocity (88.9 mph) and HR-distance (409-feet!) he has produced an ISO of .179 this year after his previous career-high mark was .096 in 2016. Adalberto Mondesi is just 23-years old and has made clear strides in his overall offensive game and power-focused approach since first arriving in the majors. While also being an elite threat for stealing bases, he is an asset of considerable value for the rest of the season even as a member of the miserable Kansas City offense, and he projects as a potential 15/30+ power/speed combo infielder for next season.

Power Fallers

Yonder Alonso - (1B, CLE)

Yonder Alonso has been on a steep downhill trend since July, and his current lack of production at the plate in September will be hard to reverse. After his big run in July, Alonso followed up by producing four HR yet a lousy OPS of .587 in 98 August AB. Now in 34 AB this month, he has somehow been much worse with zero dingers to speak of and a sad slash of .118/.143/.118. Why has Alonso struggled so badly to kick off the last month of the regular season?

First off, his strikeout rate (28.6%) and walk rate (2.9%) are both his worst figures of the season, so that immediately accounts for a portion of lost offensive production. Those aren't the only categories that have seen season-worsts for Alonso this month. His GB/FB ratio of 1.86 is his highest mark of the year and his 54.2% ground ball rate as compared to a 29.2% fly ball rate isn't very conducive to power-hitting. Although his pull rate is surprisingly at a season-best 58.3%, his hard and soft contact rates this month have been appallingly lopsided with respective rates of 25% and 33.3% that have so far netted an ISO of .000 in September. His HR-distance of 401-feet is slightly above league-average but his exit velocity of 88 mph is slightly below and is likely more telling of where his power-hitting is at right now. His problems in quality of contact on batted-balls have been snow-balling all season and have caused serious issues since the end of July. Now even Yonder Alonso's HR-volume has been suffering, and this negates a large portion of his value even within the elite Tribe batting order when considering his decaying plate discipline. Cleveland can only hope for him to shake off the cobwebs by the start of the postseason but that requires fewer strikeouts, better contact on batted-balls, and a GB/FB ratio much closer to 1.00.

Nick Hundley - (C, SF)

The San Francisco Giants have now dropped a miserable eleven games in a row, and one of the components of that broken machine is Nick Hundley, who has managed a goose-egg in the HR department with a terrible slash of .154/.241/.173 over his last 52 AB. The 35-year-old Hundley earned consideration at catcher from fantasy baseball managers when he started the year with three-straight solid offensive months, but since then has done progressively worse in his plate appearances as each month has passed. Thankfully though, his poor work with the lumber in the last couple of months is likely due to a few very fixable aspects of his offensive approach, and he could very well turn things around for a strong finish to the regular season.

Hundley has done very well lately in terms of batted-ball figures. Even in this month of immense struggles he has produced a GB/FB ratio of 1.00 with 37.5% line drives, a stratospheric pull rate of 68.8%, and confusingly fantastic hard and soft contact rates of 62.5% and 12.5%. The main problem then could be his plate discipline this month, as he has a measly 3.7% walk rate with a 37% strikeout rate. This limits his offensive opportunities considerably regardless of how often he is making hard contact. So the good news is that when also taking his 89.2 mph exit velocity into account, it appears that Nick Hundley has been consistently making some rock-solid contact on pitches throughout the year. The issue is that with his lack of raw power demonstrated by an average HR-distance of 384-feet and the fact that San Francisco is notoriously pitcher-friendly, it may be harder for him to hit for power with this current approach unless the Giants are playing a road game against a division-opponent who plays in a hitter-friendly venue. Given his track record this year, he will likely have to lower his strikeout rate closer to 25% for the remaining games of September in order to end the year on a positive power-hitting note. Even then the expectations are still conservative with respect to his offensive ceiling, with a realistic image being a mid-level BA and OBP with two knocks through the rest of the month.

Eduardo Escobar - (3B/SS, ARI)

After five straight months of fantastic offensive production and consistent power-hitting, Eduardo Escobar has taken a deep dive since the start of September, and currently holds a slash of .205/.273/.308 with a lone HR in 39 AB so far this month. A closer look at Escobar's work in September renders a clear diagnosis of the issue in his offensive performance, though it brings up a few questions about whether "El De La Pica" will be able to turn it around before the end of the regular season.

Escobar's walk rate and strikeout rate this month has been consistent with his previous work this season and both figures have remained quite tolerable. Also, his pull rate has actually reached a season-high point this month at 53.3%, but that is where the positive signs stop for September. His primary issue lies in the fact that he is hitting just 30% fly balls this month while his hard contact rate also sits at a stagnant 30% and his soft contact rate has ballooned to 23.3%. All three of those figures are season-worsts for Escobar, and even when hitting 36.7% line drives, his mediocre exit velocity of 86.8 mph makes it easy to understand how his BABIP could be just .241 in September. The optimistic way to look at this is that the limited sample of the start of this month serves as a stark outlier when compared to his monthly offensive performances throughout the season. However, to consider him a utilizable asset until the end of the regular season, his quality of contact on batted-balls needs to improve and there is never a certain timetable on that recovery process. Though it hardly tells the full story of his 2018 campaign, this sudden slump warrants extreme trepidation when proceeding forward with Eduardo Escobar.

Wilmer Flores - (3B/1B/2B, NYM)

While 2018 has been a down power-hitting season for Wilmer Flores, up until September he had still managed to produce a solid BA and OBP with consistent yet conservative power hitting. However, over the last 76 AB he has failed to notch a single yard-ball and has managed a less-than-pedestrian slash of .263/.291/.303. Flores has remained on the radar of fantasy baseball managers all year due to his consistent well-roundedness and multiple-position eligibility, but many aspects of his recent play spin a grim tale for the remaining weeks of the regular season.

It's important to understand that in terms of power-hitting, Flores doesn't possess the x-factor of raw power as evidenced by his 86.6 mph exit velocity and 388-foot average HR-distance. On top of that, even though his hard contact rate isn't typically spectacular, this month he is producing just 17.7% hard contact which has resulted in an ISO of .048. His soft contact rate has been manageable at 17.7%, but the high frequency of medium contact when mixed with a GB/FB ratio of 2.00 off of 47.1% ground balls and 23.5% fly balls doesn't make for explosive plate appearances. In addition, his pull rate is at a season-low 35.3% and his usually exemplary strikeout rate has inflated to 19% in September. This combination has resulted in the collapse of his offensive house of cards and brought his power-hitting and overall work at the plate down with it. Unless you desperately need someone to fill one of three infield positions on any given day for a lower-echelon run-scoring club, avoid Wilmer Flores.