Red Sox: Joe Kelly’s low strikeout rate is becoming a concern
Joe Kelly’s blazing fastball should have made him a strikeout machine in the Boston Red Sox bullpen, yet that hasn’t been the case this season.
Joe Kelly recorded a pair of strikeouts after trotting out from the Boston Red Sox bullpen for a scoreless 1 1/3 innings against the New York Yankees last night. Normally it wouldn’t be headline news that a reliever struck out half the batters he faced in a small sample, although in Kelly’s case it represents a promising improvement.
When manager John Farrell summoned Kelly in the top of the 7th inning, Boston trailed by three runs and the Yankees had loaded the bases. Kelly managed to get Starlin Castro to ground out on a ball hit right at second baseman Marco Hernandez, although that’s probably not the scenario Farrell had in mind when he called for Kelly. Had that grounder been a few feet further away in either direction, perhaps it sneaks through for a base hit that drives in a couple more runs and puts the game essentially out of reach.
What the Red Sox really needed in that situation was a strikeout, which have been hard to come by for Kelly so far this season. While he managed to punch out two batters after staying in for the eighth inning, that pair of strikeouts doubled his season total.
Kelly has racked up a mere four strikeouts over 12 innings of relief, giving him a 3.00 K/9 that ranks dead last in the American League among pitchers who have logged at least 10 innings.
This isn’t to say that Kelly has been awful this season. In fact, his 1.50 ERA and 1.08 WHIP are among the best on the team and right in line with his results after being converted to a reliever late last season.
More from Red Sox News
- Red Sox Nation deserves far more from Fenway Sports Group
- Bizarre trade deadline comes back to haunt Red Sox after Nathan Eovaldi departure
- Red Sox’ Moneyball-style offseason continues with Corey Kluber contract
- Rich Hill’s Red Sox departure puts him within striking distance of unique MLB record
- Red Sox offseason takes another nasty hit with Nathan Eovaldi departure
The difference is that Kelly struck out 21 batters and only walked five over 17 2/3 innings out of the bullpen last season, showcasing the potential that enticed the Red Sox into believing he could thrive as a power arm they could unleash late in games. This year his strikeout rate has not only plummeted, he’s also walked more batters (6) than he did as a reliever last year in nearly half as many appearances.
He may currently be sporting a shiny ERA, yet we can’t help but wonder how much of that is attributed to luck. His .189 BABIP is tied for the ninth lowest in the league and well below his career .300 BABIP, which clearly indicates this rate isn’t sustainable. His 5.02 xFIP paints a far less appealing picture of what his numbers could look like if his fortune on balls hit into play were to take a turn for the worse. The only way to improve that inevitability is to cut down on the walks and improve his strikeout rate.
Is there a reason for this drastic drop off in strikeout rate or is it merely the mirage of a small sample size?
More from Red Sox News
- Red Sox Nation deserves far more from Fenway Sports Group
- Bizarre trade deadline comes back to haunt Red Sox after Nathan Eovaldi departure
- Red Sox’ Moneyball-style offseason continues with Corey Kluber contract
- Rich Hill’s Red Sox departure puts him within striking distance of unique MLB record
- Red Sox offseason takes another nasty hit with Nathan Eovaldi departure
The good news is that Kelly’s velocity hasn’t fallen off, which is typically the cause of a pitcher seeing a decline in strikeouts. He’s averaging a tick over 98 mph on his fastball and can still dial it up to 100, according to PITCHf/x data provided by FanGraphs.
Kelly’s issues seem to be more related to location, as opposing hitters aren’t chasing his pitches outside of the zone as frequently.
Kelly’s fastball remains his most trusted option, throwing the heater 34.5 percent of the time. Last year he produced an O-Swing% of 28 percent with his fastball, which has fallen to 23.5 percent this year. His O-Swing% has declined even further on his slider, from 31.3 percent last year to 25.8 percent this season, while his curveball has fallen off from 27.3 percent to 14.3 percent.
Hitters laying off pitchers outside of the zone results in fewer swings and misses that strikeout pitchers rely on, while it also explains the increase in walks. Since hitters are swinging at a higher rate of his pitches inside the zone, the contact rate Kelly allows has skyrocketed – from 75.2 percent to 90.3 percent on his fastball and 70.8 percent to 80 percent on his curve.
Take a look at Kelly’s heat maps for last year versus this season. One thing that stands out is the higher percentages of pitches well outside of the strike zone.
Joe Kelly heat map 2016 vs 2017. Notice the higher percentage of pitches well outside the zone. #RedSox pic.twitter.com/jk30cehYfo
— Sean Penney (@spenney83) April 27, 2017
This explains why Kelly is getting fewer hitters to chase pitches outside of the zone. In order to generate more swings and misses he’ll need to tempt hitters by placing those pitches a bit closer to the plate. Otherwise hitters will lay off those pitches with little concern of it being a called strike.
Kelly is still capable of throwing some filthy pitches that can generate swings and misses in the zone and he has a fastball that many big league hitters can’t keep up with. Being a bit more aggressive in attacking hitters would reduce the number of pitches well outside the zone that they mostly ignore. It would also cut down on his walks and limit the number of counts where he falls behind, giving hitters an advantage.
Keep in mind that we’re still dealing with a tiny sample size, so we should expect Kelly’s strikeout rate to trend upward. However, as we’ve seen, there are some notable reasons for this decline that suggest he won’t reach his potential as a power reliever until he makes some adjustments to his approach.
Next: Porcello making effective adjustment from rough start
The Red Sox put Kelly in the bullpen expecting the velocity on his fastball to make him a lights out strikeout machine. The potential is there to miss more bats, but it hasn’t happened yet. The higher contact rates haven’t hurt Kelly this season, but he’s playing with fire if he expects that to continue.