Jeurys Familia is striking out a lot of batters lately

After a low-strikeout start to 2016, Jeurys Familia is striking out batters at a high rate lately. He has steadily increased his strikeout rate by month, jumping from a below-average 17% in April to an elite 33.9% in August and September. The average relief pitcher strikes out 22.5% of the batters he faces.

In April, Familia ranked 148th out of 182 qualified relievers in strikeout rate. In the second half of the season, Familia has jumped to 30th out of 156 qualified relievers in strikeout rate.

Research at Baseball Prospectus indicates that strikeout rate stabilizes for pitchers around 70 batters faced, making the sample a reasonably reliable indicator of strikeout skill level against those past 70 batters. Familia crossed into that threshold dating back to July 28. Since that appearance, Familia has a strikeout rate just under 34%. For some perspective on how good that is, a 34% strikeout rate would rank just outside the top 10 for qualified relievers if it held all season.

What first jumps out from watching him all year is that Familia’s slider has retaken some of that late, sharp, nasty break that was missing early this season. This 89 mph slider is from the last week of August.

The data supports the observation. Familia’s slider is generating an outstanding swinging strike rate of 26.2% in his last 70 batters faced from the end of July until now, up from a below average 14.8% on his slider in April. The major league average swinging strike rate on a slider is 15.9% in 2016.

Familia’s sinker and slider velocities have also risen since the early part of the year. In April, PITCHf/x recorded his slider velocity at 85.4 mph, which is way down from April 2015, when it sat 88.2 mph. Familia’s slider velocity is still noticeably down from last year’s 89.3 mph, but it’s climbed back up to 87.1 mph in his last 70 batters faced and 87.7 mph in four September appearances. His sinker velocity has increased 1 mph from April to his last 70 batters faced, from 95.4 mph to 96.4 mph.

Familia also had a second-half spike in strikeout rate in 2015, although for different reasons. He increased his strikeout rate to 32.7% in August and September of 2015 from 25.3% in months prior largely because of a ridiculous 93 mph splitter he developed in the second half that ate lefties alive. Familia’s splitter hasn’t really been used in 2016; Brooks Baseball pitch classifications have it at only 2% usage in 2016, with it at 1% in his last 70 batters faced. In the second half of last season, Familia used his splitter at a 15% rate.