Fastball Velocity Declines

After taking last week off, I’m back to make a brief examination of some pitchers who worry me with their declining velocity. There is no good news today. It’s just some pitchers who could be headed for a demotion or the IL.

Some quick housekeeping. The entire list of pitchers and their fastball changes are available on this spreadsheet. With more data available, I examined at the past two weeks of data for the in-season information. Finally, an injury value of -100 is bad and +100 is good.

Note: Sorry for the short article but real life got in the way and I want to make sure I have time to go through the AL lineups tomorrow.

Carlos Rodon
2018 FBv: 93.0
2019 FBv: 91.5
Last two week: 90.6

Note: This was written before he went on the DL

The 26-year-old seemed to have finally righted the boat after dealing with injuries and wildness for several seasons. In his first five starts this season, he had a 2.89 ERA and 11.3 K/9 (huge jump over 8.8 K/9 career value). Two blowup starts came against offensive powerhouses Detroit and Baltimore and now he has a 5.19 ERA fueled by a 4.4 BB/9.

He’s tough to put a value on. The velocity drop is discouraging and could mean another IL trip. The increase in strikeouts is from throwing his slider more (26% to 37%) but since the slider has only a 34% Zone%, the walks are also up. I could say to start him against weak opponents, but Detroit and Baltimore lit him up. I guess an owner can start him if they just need strikeouts and doesn’t care one bit about their ratios.

Jeremy Jeffress
2018 FBv: 95.3
2019 FBv: 91.9

I must start with this graph:

See a trend? For the past two seasons, Jeffress has started slow but built up his velocity. He needs to do it again.

His owners must be hooked in by his 3.86 ERA. It’s not great but it’s better than his near 6.00 ERA estimators from a sky-high walk and home run rate. He’s a bench for now until his velocity starts ticking up.

Homer Bailey
2018 FBv: 93.1
2018 FBv: 92.5
Last two weeks: 90.3

There are several items to like about Homer Bailey this season. 9.0 K/9. ERA estimators near 4.00. Just a 0.90 HR/9. But he has a 5.70 ERA and the history of being Homer Bailey. There is no reason to roster him at this moment until he puts together a few good starts.

J.A. Happ
2018 FBv: 92.0
2019 FBv: 90.6
Last two week: 90.6

Happ’s velocity hasn’t rebound yet this year. For a pitcher whose results walk a tight rope, the loss makes him way too hittable since he can no longer miss bats. His strikeout rate (6.6 K/9) is a nine-year low and his home runs (1.9 HR/9) is the highest over the same time. Historically, his fastball needs to be over 91.5 mph to be effective. Bench but don’t drop.