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Michael Fulmer’s slider is his ticket to ace status

Fulmer is already really good, but the route to greatness goes through his breaking ball.

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New York Yankees v Detroit Tigers Photo by Gregory Shamus/Getty Images

Michael Fulmer is a name now. The 2016 AL Rookie of the Year came back with a solid sophomore season, and was on everyone’s mind this offseason as the subject of trade speculation. Fully recovered from nerve transposition surgery on his elbow in the offseason, Fulmer aims to take the reins as the Detroit Tigers’ ace in 2018, and perhaps beyond. To that end, he and new pitching coach Chris Bosio have keyed on his slider as their focus for improvement this season.

Fulmer is plenty good already. Before the nerve issue really became a plague on his stuff, Fulmer was on track for a fine second MLB season. If he does nothing more than stay healthy, pitch like he has already shown himself capable, and clear 180 innings (a feat he has yet to manage), it would be plenty good enough. His value to the Tigers, both on the field and on the trade market, would be quite high. But the potential remains for Fulmer to develop into an elite starter capable of going toe-to-toe with anyone in the game.

Right now, the ZiPS projection for Fulmer in 2018 isn’t very impressive. A 3.94 ERA and 3.96 FIP in 162 innings is the expectation. His Steamer projection is fairly similar, though it predicts 185 innings. In both cases, Fulmer’s low strikeout rates are the cause of these average projections. While there’s a solid argument to be made that neither system is incorporating Fulmer’s ability to suppress hard contact, the lack of strikeouts continues to have him looking like an above-average, but not elite starting pitcher.

The best starters in the game consistently strike out a batter per inning or more. Fulmer isn’t in that league yet. Instead, he was 38th among qualified starters in swinging strike rate in 2017, right after Julio Teheran and noted strikeout artist Rick Porcello. Fulmer was 48th in strikeout rate, fanning 16.9 percent of batters. He was 23rd in 2016, posting a 20.4 percent strikeout rate. Considering the raw stuff Fulmer possesses, one would think he could be a good deal better in this regard.

Honing the slider with Rapsodo

Despite coming up as a power fastball-slider pitcher, Fulmer actually gets more whiffs with his changeup than the slider. While calling the slider a weak link is an exaggeration, getting more whiffs on that pitch is a key for Fulmer in 2018. He already generates a ton of weak contact with the pitch, typically on the ground. It’s already valuable to him — he threw it 21 percent of the time last year — but it’s not yet the wipeout slider it could be. If he can sharpen it and build on his strikeout rate, Tigers fans may have a perennial Cy Young contender to watch every five days.

Fulmer and Bosio have identified the slider as their number one focus heading into the 2018 season, and they have a new toy to help them improve it. The Tigers have begun using a Rapsodo pitch monitoring unit — get yours here! — for real time data in bullpen sessions. Fulmer doesn’t sound like he knows to what use he will incorporate this data just yet, but he is at least interested.

“I haven’t looked at the data yet,” said Fulmer, who threw 30 pitches. “I am curious to see the spin rate on my release point and finish. I’ve never been big on spin rate. They are trying to encourage it. I hope I can get behind it.”

“I’m more interested in seeing the spin rate on the slider, just because I rely on that to get guys to hit the ball on the ground. The more spin you have, the more depth you can get on the slider.”

This is all music to my ears. Being able to experiment with his grips and the delivery changes he and Bosio are working on, and see the detailed, real time results of that work, seems like a great tool to re-enforce good habits. You also get instant feedback to compare with how the release or the spin on a pitch felt coming out of the hand.

For Mr. Fulmer’s information, his slider averaged 2371 rpm in 2017, down from 2416 rpm in 2016. This is basically league average spin, but with above-average velocity. Fulmer might be able to do better than that, but improving his slider is probably going to have more to do with his release and perhaps the velocity of the pitch than its actual spin rate. Without major changes elsewhere, spin rates are reasonably consistent.

Delivery changes

Bosio has had Fulmer working on a softer front leg landing since their first phone call this offseason. In a piece for The Athletic, Katie Strang reported another adjustment Bosio was looking for.

“Bosio sent Fulmer a still frame of Fulmer in the release point of the pitch, and told him he wanted his back leg higher. He wanted his heel in line with his head at the point of release, with Fulmer’s arm at mid-shin. The next time Fulmer threw, he incorporated the small tweak and his slider, already his most potent pitch, felt even better.”

In short, Bosio is trying to moderate the effects of Fulmer’s crossfire delivery by getting his front side into a more athletic, flexed position. It doesn’t sound like they are interested in messing with Fulmer’s delivery to the point of eliminating the crossfire in his motion. Rather, Bosio is trying to get Fulmer in better position to moderate the extremes in his delivery and help him stay on top of the ball. Either that, or this is an elaborate game of Twister.

Because Fulmer steps noticeably to the third base side of his direct line to the plate, he is able to hide the ball a beat longer. However, he also has to compensate with his upper body because his hips are blocked. He releases the ball well before his hips square with his target line. That can lead to his arm slot flattening and a loss of depth on his pitches, particularly the slider. This crossfire motion also makes it tougher to throw downhill and locate around the bottom of the strike zone. It may also be a little harder on the shoulder than one would like to see.

By the sound of it, these adjustments struck a chord with Fulmer. The challenge is to integrate them without sacrificing anything on his fastball and command. All reports indicate that he is throwing the ball well so far in spring training. His first Grapefruit League outing on Monday went just fine, but there wasn’t much to take away beyond the fact that he’s healthy. For now, that’s enough.