Of all the surprising stories this season, Matt Belisle’s rise to prominence takes the cake for least expected. The 30 year old reliever for Colorado has thrown 47 innings this season. That’s nothing extravagant; he did throw 31 innings for the Rockies last season after all. What is alarming is that he’s striking out more than one batter per inning; this from a guy who split duties between starting and relieving through most of his career and still has a career K/9 under 6.5.
Looking for a change in his pitch usage is futile. He’s throwing the same pitches at about the same rate as before, the results are just drastically improved with a heaping of added swinging strikes. Here are Belisle’s swinging strike rates this season on pitches he’s thrown more than 50 times:
Here are the whiff rates for the same three pitches last season:
Since it’s only his fastball and slider that have been affected this season, my guess, and this is clearly only a guess, is that it has something to do with sequencing. Luckily, we have the ability to easily check his pitch selection by count on his splits page. Sure enough, it seems Belisle is being far less aggressive with his fastball after getting ahead in the count.
That would seemingly be a common trend amongst pitches; after all, the mantra about establishing the fastball and all that jazz is still mentioned across quite a few telecasts on any given night; but it’s especially true for Belisle. When he gets to two strikes on a batter it’s time for the breaking stuff. On 1-2 counts he’s using his curveball nearly 50% of the time as opposed to using it only 22% last year.
Who knows whether the continued usage shakeup is the only reason or will continue to mystify hitters that oppose Belisle, but through this point in the season, he’s been pretty impressive.