DINGERS FROM THE 6IX
by Quinn Sweetzir
With three blown saves in his first four save opportunities of the season, it’s safe to day that Roberto Osuna’s start in 2017 has been less than ideal. After starting the season on the disabled list Osuna has come back, only to allow 5 runs in first 6 innings of the season. In addition, his struggles in both spring training and at the World Baseball Classic have put Jays fans on high alert.
Among the more obvious concerns for Osuna’s struggles is a velocity drop, as his fastball has decreased 1.4 mph. Several individuals have pointed to this as the most significant reason for Osuna’s struggles. After all, we saw what a velocity drop could do to a reliever when we watched Drew Storen pitch last year, and he wasn’t very good.
Usually, the biggest impacts of a velocity drop is a reduction in the quality of a pitcher’s stuff, which often leads to a reduction in strikeouts. Storen suffered a rather dramatic 2.2 mph decrease in velocity from 2015 to 2016, which led to a dip strikeouts from 10.96 K/9 to 8.36 K/9. However, Osuna hasn’t suffered the same fate, as his K/9 is down from 9.97 in 2016 to 9.00 early in 2017. This is a small sample size but it is something to pay attention to in the coming games as a reduction in stuff often leads to a reduced strikeout rate.
However, one similarity between Osuna’s and Stroen’s velocity drops is the increased amount or contact these pitchers allowed. In both cases contact rates both in and out of the strike zone increased by around 6%. As you can see, there are comparable between the dominant to replacement level Drew Storen, and the dominant to TBD Roberto Osuna. I should however emphasize this sample size is incredibly small, and we should understand that drawing real conclusions this early in the season is virtually impossible.
This leads me to explore an entirely new idea, which is that Roberto Osuna needs to stop throwing his sinker. Late in 2016, Osuna struggled somewhat, allowing a 3.96 and 4.10 FIP and xFIP respectively. During September, Osuna increased his sinker usage by over 20% from his season average to that point. This trend has continued in 2017, with his fourseam fastball usage decreasing to 29.90% and sinker usage rising to 26.80% in 2017.
There is a rather significant problem with Osuna’s sinker however, and that is it doesn’t really sink all that much. Just consider the differences between Osuna’s sinker, and that of his teammate Marcus Stroman, who’s sinker is significantly better.
A you can see, the difference between the sinker of Osuna and Stroman is dramatic. Stroman’s sinker sinks around 6 or 7 vertical inches than Osuna’s, while Osuna’s averages around 2 or 3 inches. The problem with the sinker is that is if the vertical movement is insignificant, then it becomes a slower version of a fourseam fastball.
For his career, Osuna’s sinker is about 0.7 mph slower than his fourseam fastball, and when you combine this with his with the overall velocity drop he has suffered from this season, his velocity on sinkers with minimal movement is about 2 mph less than his average fastball velocity in previous seasons. Basically, more than a quarter of Osuna’s pitches have been close to straight fastballs which are 2 mph slower than they have been in the past.
The conclusion I’ve reached from this article is that Roberto Osuna needs to stop throwing his sinker. He struggled when he threw it last season, and when he throws it this year its lack of movement is exposed when its thrown 2 mph slower than your fourseam fastball career average. Osuna’s velocity drop on its own is not enough to cause sustained struggles, however regularly throwing slower sinkers which don’t sink is probably the most alarming aspect of Osuna’s early season struggles to this point.