Power Hitting Risers & Fallers for Week 15 - Buy or Sell?

Home run risers and fallers for Week 15 of fantasy baseball. Nate Green evaluates power increases or decreases, and players who could be buy or sell candidates.

Welcome to the All-Star Break edition of Power Hitting Risers & Fallers. All stats are full season through Sunday, July 7 (unless otherwise noted). For the break, this week's risers and fallers were selected somewhat more scientifically than usual. Everyone who had 100 plate appearances in both 2018 and 2019 had the number of plate appearances between home runs calculated (e.g., 10 HR in 200 PA returned a value of 20) both 2018 and '19, and then the difference between the seasons was calculated -- if the PA/HR rate got a lot smaller, that's a riser, and vice versa for a faller. Risers needed 10 or more home runs this season (2019) and fallers needed 20 or more home runs last season (2018) to make the tables.

By this standard, who were the first half's biggest risers and fallers? Read on to find out. The top 12 are shown, and the most subjectively interesting written up.

Weekly reminders: EVAB (pronounced ee-vab or ev-ab) is simply exit velocity on "air balls" - meaning fly balls and line drives, as shown on Statcast. Isolated power -- ISO -- is slugging percentage minus batting average, and so xISO is xSLG minus xBA. The Statcast Search feature is used to obtain partial season Statcast numbers. The league-wide ratio of barrels to home runs is historically around 67-70%.

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Power Risers

Josh Bell (1B, PIT)

Although he only ranks 11th by this metric, in pure volume Bell is the most impressive riser of 2019 so far. He is the only player on the above list who is likely to hit 40 home runs. It makes sense; most players who top the home run leader board one year were probably pretty good the year before, while players with the largest power spikes are probably starting from a very low point and can only go so high.

Bell's batted ball profile has jumped immensely this season as well. Instead of hitting the ball 90.0 mph at 9.2 degrees on average, he's hitting it 93.3 mph at 10.9 degrees. It's been enough to more than double his barrel rate, from 7.0% of batted balls last year to 14.7% so far this year. No wonder his power has spiked so significantly.

It also hasn't hurt to have a few more barrels turn into bombs. Last season, Bell needed 28 barrels to homer a dozen times. This year, Bell's 27 bombs on 39 barrels is right around the league average.

Brett Gardner (OF, NYY)

Probably the most surprising name on the list, as Gardner hasn't gotten much hype for his campaign so far. Unfortunately, that's not entirely undeserved by Statcast metrics. Somehow, Gardner has hit his 15 home runs with just nine barrels. Check out some of this contact. His average home run has only gone 378 feet. Surprisingly, seven of his 15 homers have come on the road, but if you watch the shortest homers, they all use Yankee Stadium's short right field porch.

Gardner's launch angle has jumped, from 8.4 degrees to 12.3, but his exit velocity essentially has not, from 87.3 to 87.7 mph. His EVAB has tracked similarly, 91.7 mph last year and 92.0 mph this year. The launch angle has produced a few more barrels per plate appearance, but Gardner's home run total is a bit flukey. He's running a .470 SLG that is a full hundred points higher than his .370 xSLG.

Gardner could continue hitting home runs thanks to his home park, but it's a risky proposition nonetheless.

Willson Contreras (C, CHC)

The other three catchers on the list -- Perez, Vazquez, and Garver -- have all emerged as strong hitters in 2019, but Contreras has re-emerged after an underwhelming 2018.

If you just look at exit velocity and launch angle, Contreras' hitting was slightly off in 2018, but it wouldn't appear significantly so. He hit the ball 87.1 mph at 5.9 degrees in a successful 2017 season and 87.0 mph at 6.8 degrees in 2018's disappointment. And yet his xSLG fell from .494 to .370 despite a consistent strikeout rate (22.9% in '17 and 22.1% in '18). Now averaging 87.7 mph at 7.6 degrees, Contreras has rebounded to a .470 xSLG. And his barrel rate also shifted, from 10.3% of batted balls in 2017 to 7.3% last year and 11.4% so far this season. All with a slight uptick in strikeouts.

Contreras doesn't have a ball-crusher's profile, and his 21 barrels don't quite support 18 homers. But last year does appear to be a blip, and if he stays healthy, he should easily clear his previous career high of 21 home runs and challenge 30.

Jason Heyward (OF, CHC)

First, the good news for Heyward. He's upped his exit velocity/launch angle average from 88.1 mph at 9.4 degrees last year to 89.3 mph at 12.0 degrees this year. That's led to a barrel rate increase, from 2.9% of batted balls (11 total) last year to 5.2% (12 total) this season.

Heyward has also ended a much higher of plate appearances without contact: his 8.6 BB% and 12.3 K% rate last year are now 12.0% and 17.3% this year, respectively. That's several fewer opportunities to go long, yet he's doing it much more often per plate appearance.

Despite all those positive signs, Heyward's expected slugging rate has fallen a bit, from .400 to .391. Because of a 14-point xBA drop, his expected isolated slugging is up ever so slightly from .120 to .125, but not nearly enough that Statcast believes in the power gains. Like Gardner, Heyward has more home runs than barrels. Unlike Gardner, Heyward doesn't have a predictably reliable fence he can plop a non-barrel over, so it seems much less likely that Heyward will continue as he has.

Orlando Arcia (SS, MIL)

Arcia has managed to spike his power numbers yet still remain bad. And yet there have been clear changes in the contact profile to support the modest bump, as he's gone from averaging 85.6 mph at 3.3 degrees last year to 87.0 mph at 6.1 degrees now. This has lifted his xSLG 74 points while his xBA has only risen 11, indicating more power. And yet, his .406 SLG is higher than his expected .360 rate.

So while Arcia is a legitimately better power hitter now, there's nothing to chase here. His presence on the list is attributable almost entirely to just how bad he was last year.

Power Fallers

Aside: Interesting that, for entirely different reasons (La Stella an injury, Herrera a crime-related suspension), the top riser and top faller will miss most or all of the rest of the season. They'd be more interesting to discuss if they'd actually play in the second half.

Jose Ramirez (3B, CLE)

It should surprise no one to see Ramirez on this list. His struggles are well-documented. Blame has generally been assigned to too-high of a launch angle, which is now 21.5 degrees. But it was 18.8 degrees last year, which worked out pretty well. There's no real hard line of "too high" -- Jay Bruce, for example, is doing fine this year at 22.5 degrees. Gary Sanchez, Mike Trout, and Anthony Rendon are all above 20 degrees as well.

But it's possible that the extra elevation plus less exit velocity when he does elevate has become a lethal combination to Ramirez. When Ramirez does elevate, he's posting just a 90.9 mph EVAB. That was only 92.4 mph last year, but it's still a noticeable drop. The resulting fall from a .474 xSLG to a .405 makes sense in that context.

Ramirez also had 43 barrels last season and 15 this year, so his ratio of home runs to barrels has gone from much higher than the league average to much lower. Perhaps that will even out the rest of the season, but it's almost impossible to try and predict what Ramirez will show in the second half. Owners have to hope there's some sort of recovery even if they don't know what it would look like.

Mookie Betts (OF, BOS)

Betts' power tumble is masked a little bit by the 13 home runs. Most MLB hitters would probably accept his .272/.392/.467 line, but Betts hit an electric .346/.438/.640 last year.

And it's not mysterious what's happened to Betts contact-wise, as his Statcast numbers are down across the board: 90.6 mph at 17.5 degrees instead of 92.2 mph at 18.3 degrees; barrels on 10.8% of batted balls instead of 14.1%; a .511 xSLG instead of .610, a 43.6% hard hit rate instead of 50.2%.

Notably, however, Betts' 2019 Statcast numbers are also better than what he did from 2015-17. His 2019 campaign does not yet measure up to 2016 despite much better Statcasts this season. One might expect some improvement (noting, for instance, the 44-point gap between his SLG and xSLG), but 2018 may also just have been a career year.

Mike Zunino (C, TB)

Zunino has retained his usual high-teens/low-twenties launch angle, going 18.8 degrees this season. His exit velocity is 89.6 mph this year after 89.5 last year. He's also cut back on the strikeouts, which would be incredible to say about almost any other player with a 30.2% K rate.

But it's been a disastrous campaign. It probably could be better; Zunino has a .402 xSLG, just 16 points less than last season. But whereas Zunino was nearly in line last year (.410 SLG), he's way off line this year at .324.

Zunino's 2018-19 experience has been the reverse of Arcia's; the Milwaukee shortstop is less bad this year but still bad, while Zunino was less bad last year compared to being even worse this season. Sure, maybe his home run drop shouldn't be this severe, but he's not someone you want to be banking on in any format.

Stephen Piscotty (OF, OAK)

Piscotty is another player, like Contreras, for whom exit velocity and launch angle don't tell the full story. Last year, Piscotty's 88.5 mph at 13.1 degrees was good enough for 42 barrels and 27 home runs, but this season's 88.8 mph at 12.5 degrees has only produced 18 barrels and nine home runs -- or, prorated to the same number of PA, 33 barrels and 17 homers. It's not an EVAB issue for Piscotty, either, whose flies/liners are exiting at 93.1 mph this year after 93.4 mph last year. Most likely Piscotty has achieved a similar EV/LA through a less productive distribution this year, hence the decline in barrels despite a consistent average batted ball.

Last year, Piscotty had a BA/SLG of .267/.491 which fit almost perfectly with his xBA/xSLG of .266/.488. This year his expected BA is back in line with his actual (.239 to .242) with a slight underperformance in SLG (.391) to xSLG (.416).

Piscotty, of course, is also on the IL with a knee sprain. It's unclear then how he will hit the ball whenever he returns, which should be sooner than Oakland immediately suspected. A bit more luck could help some, but the severity of his home run fall is nonetheless trackable to the drop in barrels and expected slugging rate, so it's not clear how much trust fantasy owners should have in him going forward. The injury only makes his ROS production more questionable even once he returns.

Jesus Aguilar (1B, MIL)

A lot of the power fallers, like Piscotty, have dealt with injuries in 2019. Piscotty, Pollock, Peralta, and Carpenter are both on the IL now. Shaw is in the minors. Molina is active despite not playing since the Thursday before the break and his thumb may still be bothering him. This pretty much leaves Aguilar, who has no such excuse, as the last faller to look at.

And his 2019 power profile is less depressing than it once was. Everything is still down from last year, excepted for a plateaued exit velocity, but he's got a respectable .452 xSLG now. His actual SLG remains .385. Aguilar homered three times in the last series before the break to show some life as well.

Nonetheless, Aguilar is on the bench a lot. He sat all of a 1-0 loss on July 3, and made only a fifth-inning pinch hit appearance on July 6. If his power starts to catch up with his expected slugging, there could be a second half turnaround here. But he needs the chance to show it.

Last Week's Risers

Last Week's Fallers

More 2019 Fantasy Baseball Advice