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.