Using Spin to Identify Two Underrated Free Agents

The pitcher with the highest fastball spin rate in baseball in 2016 was also the first free agent signed this offseason. Maybe that’s just coincidence — Andrew Bailey was re-signed by the Angels to a modest one-year, $1 million deal with incentives, so it’s not like it required a ton of courting — but there are plenty of front offices who’ve designated at least one analyst to comb through the free-agent wires to find a pitcher with good spin rates. Let’s play along.

Of course, we can only play along so much: the major-league front offices have minor-league spin rates easily accessible in their databases, so they don’t have to go looking far and wide for data. Also, spin rates alone don’t tell the whole story, especially when it comes to changeups and sliders. However, we know this: given equal velocities, the fastball with the higher spin rate is superior fastball — and that looks to be true for curveballs, too. (Check the curveball tab of that linked spreadsheet, courtesy Jeff Zimmerman).

Fastballs are easy, so let’s take a look at the best free-agent fastballs by spin. I’m going to add a column devoted to putting that spin in context. Spin goes up with effective velocity, generally.

So I bucketed all fastballs by their effective velocity, found the average spin rate, and then compared each player’s spin rate to their effective velocity average, where 100 is average. I’ve sorted the list for Effective Velocity Indexed Spin (EVIS) here.

That’s a decent spin rate on the four-seam from Peavy, especially when you consider how slow he’s humping it up there these days. He’s actually in baseball’s top 10 by this measure, sandwiched between spin kings Drew Pomeranz and Rich Hill. Last year wasn’t a great year for Peavy, and it came in a pitcher’s park, so the league may not be chomping at the bit for his services. What about making him a reliever? Maybe he could be a sneaky play with more of those four-seamers at his disposal?

We know Rich Hill and Aroldis Chapman will get money, but Casey Fien could also get a major-league deal. Not only did he show elite spin for his velocity, but he also had the second-best whiff rate of his career. Sometimes you have to look past the home runs, especially in a 40-inning sample, even when you’re talking about a pitcher who cleared waivers and was outrighted to Triple-A this past September.

In a way, this methodology could help future teams identify relievers who still have life on their pitches despite iffy results. Anything can happen in a reliever’s sample, but spin rate is more stable in smaller samples and has some capacity to speak on the health of the pitcher. David Hernandez and Neftali Feliz both gave up a few too many homers, and both have struggled with health in the past, but their underlying spin speaks well of their ability to contribute to a major-league pen in 2017.

Jered Weaver’s spin looks average until you look at it in the context of all fastballs under 87 mph. By grouping all of those together, we get 31 pitchers. But it’s still hard to use this finding to advocate the signing of the one guy who averaged 84 mph on the fastball. The only guys with slower fastballs threw knuckleballs, after all.

Curves!

The first guy on the list just signed with the Astros today. You’ve heard about the second guy’s curve spin rate ad nauseum by now. The second guy will get good money. The fifth guy has signed with the Angels already. The third guy — Junichi Tazawa — did decently and should get some money and guaranteed years from a team this offseason. Jhoulys Chacin is interesting because he felt to had to shelve that curve in Coors, and it might be his best pitch.

But there in the middle of the list, we have Fien again, who in any other year would probably be headed for a minor-league invite after the year he had. But in the Era of Spin, he might be find himself with a major-league offer in the coming months. And Peavy again! Maybe he should focus on being a four-seam/curve guy instead of throwing eight different pitches.

Fien and Peavy. Peavy and Fien. Both pitchers recorded a curveball spin rate within the top 20% of all pitchers — in addition a fastball spin rate within the top 5%. That’s a great combo on which to rely. The agents of those two pitchers, at least, should bookmark this page for future reference. It may make a difference with the right front office.