Tyler Glasnow’s Struggles and Bauer Units


Tyler Glasnow has struggled so far in the early going.  So far he has not lived up to the hype of his prospect ranking, but it is still early.  There is one quick fix that he can make that will help.

Back in March, I wrote about the Bauer Unit (spin rate/velocity) on the fastball in regards to the Pittsburgh Pirates starting rotation.  The idea came from Kyle Boddy of Driveline Baseball, a biomechanics research lab in the state of Washington. Driveline research concluded that,

"“League average Bauer Units -> look into developing a 2-seamAbove average Bauer Units -> try to throw middle/up in the zoneBelow average Bauer Units -> try to throw middle/down in the zone”"

In 2016, the league average Bauer Unit was 23.9 when you using the data from baseball savant.  When you’re throwing a league average fastball, choosing to go with the 2-seam fastball can make a difference in results.

Tyler Glasnow possess a 170 ERA-, 122 FIP-, and a 185.2 DRA-, all three of which are not a good sign, as 100 is league average, and the lower the better.  But the good news for Glasnow is he is giving up weak contact, and that weak contact comes with an incredibly high batting average on balls in play (BAbip) of .368.  On a post made May 28, Jake Smail of Cannon Ball corner found that,

"“So far this year, Glasnow has given up good contact on only 9.16% of the balls put in play against him. That has him ranked 26th best in the league, ahead of guys like Jacob deGrom, Dallas Keuchel, and Clayton Kershaw. He’s also ranked above teammates Chad Kuhl, Gerrit Cole, and Ivan Nova.”"

Glasnow isn’t giving up good contact, which is a great sign for improvement, especially if he can lower his walks.  An additional way for Glasnow to improve his ability is by changing to a 2-seam fastball, and by doing so, go away from the 4-seam.

In 2017, Glasnow’s 4-seam has averaged 93.7 miles per hour with a spin rate of 2222 rpm, which produces a Bauer Unit of 23.7, which is near league average.  When having a league average Bauer Unit on the 4-seam, it is suggested by Driveline to go to a 2-seam.

So far this season, Glasnow has thrown his 4-seam 45.29 percent of the time.  It has produced opponents hitting .355 with a .645 slugging.  The average exit velocity of 87.2 miles per hour and average launch angle of 18.5 degrees has given an expected wOBA of .400.  He has only thrown his 2-seam 18.83 percent of the time.  It has produced an average of .380 and slugging of .560.  Opponents are getting hits more often, but have less power.  Furthermore the 86.9 mph average exit velocity and 5.1 degree average launch angle have helped produce an expected wOBA of 0.338.

Next: Jameson Taillon Shines in Rehab Start

Glasnow is not losing velocity by making a switch, both pitches average 93.9 miles per hour, and the 2-seam is perceived at 96.37 mph and the 4-seam at 96.46 mph.  He is not allowing hard contact to begin with, and when he throws his 2-seam fastball the expected results have been much better than when he throws his 4-seam fastball.  It’s a simple switch to make, and one that can help make Tyler Glasnow a better pitcher.

*Numbers from fangraphs, baseball prospectus, and baseball savant