What’s Up with the Angels and Spin Rates?

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Updated: February 23, 2017

A few months ago, I came across a FanGraphs post by Jeff Sullivan (You can read it here). In it, Sullivan showed how the Angels were taking a cheap gamble on Andrew Bailey due to his extremely high spin rate. It was one of the first moves of the offseason for the team and it made sense since the Halos had the top defensive shortstop in all of baseball.

But as the offseason unraveled, the team got better defensively up the middle and at first and made a bunch of small moves to try and patch up the bullpen. I knew that the team was focusing on defense, since they were middle-of-the-pack defensively last season, but what really struck me this offseason was the fact that the Angels kept claiming relievers off of waivers that had pretty bad track records. I decided to dig a little deeper into Billy Eppler’s bullpen, uh, we’ll call it makeover, and what I found was that the Angels not only took a gamble on Bailey and his spin rate, but also bet on nearly every offseason signing this winter.

I first realized what the Angels were doing when they acquired Austin Adams from the Cleveland Indians earlier this month. In response to the trade, the team DFA’d Deolis Guerra, one of the key pieces to last season’s bullpen. While the bullpen was a mess last season, Guerra was fairly consistent, so it raised some question marks. Why would the Angels part with a reliever with a 3.21 ERA in favor of one with a 9.82 ERA? Well, that traces back to spin rate. Guerra had a spin rate of 2232.0 on his four-seam fastball. Adams’s fastball spun at 2284.0. The major league average last season was 2241.0.

To be fair, Adams throws a lot harder than Guerra, but the numbers are still there. The spin was definitely affected velocity, but what I think what the Halos were really looking at was groundball and contact rates. Adams has a career GB% of 46%, while Guerra sits at 41.1%. Batters had a contact percentage of 75.9% against Adams and 79.5% against Guerra. Not a big difference, but it is clear that the Angels wanted to move away from pitchers like Guerra this offseason in favor of those that can whiff batters, yet also limit contact.

It wasn’t just the Adams move that suggested the Halos vision, but also most of their offseason signings. Eight pitchers signed this offseason have above average spin rates on at least one pitch, including four on the active roster. Projected fifth starter Jesse Chavez has a spin rate of 2376.0 on his fastball, 135 points higher than the league average, yet he signed for just $5.75 million. Out of the eight pitchers signed or acquired, only two were signed to major league deals. Billy Eppler is taking a cheap gamble on this years bullpen and it might just pay off.

If higher spin rates do in fact lead to more ground balls, then the Angels have the defense to go with it. The bullpen might not be as bad as it has been projected if spin rates are in fact the answer. Only two projected bullpen pieces have spin rates lower than the league average. It will be interesting to see if spin in fact makes a difference.

Spin has been looked at in several different ways. Jonah Pemstein at FanGraphs wrote an excellent piece on how spin affects the outcome of each pitch. In it, he includes several graphs, including one on contact rates. I think this is exactly what the Angels are looking at. As more spin is added to the ball, contact is being made less and less. Couple spin rate with velocity, and you can see where the Angels are headed. Several of their offseason acquisitions throw north of 94 MPH. If this is in fact what the Halos are shooting for, we may see a bullpen full of strikeout guys. There’s no telling exactly how good the ‘pen will be this season, but spin rates provide a focal point that can predict how the bullpen will perform.



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