Post-Trade Deadline Pitch Mix Changes: Starters

Every year, a huge throng of pitchers changes teams at the trade deadline. It happens for obvious reasons: teams with postseason aspirations and second-division pitching staffs try to augment their squad, juggernauts shore up their bullpen, or any of several variations on those themes. For the most part, it’s a simple re-allocation of good pitching: teams that don’t need it this year trade pitchers to teams that do, and reap prospects or otherwise interesting players in return.

Sometimes, though, teams make trades for a slightly different reason. Pitchers aren’t static; you can’t call someone up on the phone and trade for a 3.40 ERA, or 2.4 WAR per 200 innings pitched, or anything of the sort. You trade for a pitcher, and as we detail frequently in the electronic pages of FanGraphs, pitchers change the way they approach their craft all the time. They might take a new approach, or learn a new pitch, or switch roles. Learning a new pitch isn’t practical in the heat of a playoff chase, but changing the allocation of existing pitches is far easier. Let’s take a look at two starting pitchers who have changed their pitch mix significantly since being traded at the deadline, as well as two others who have made smaller changes.

Jordan Montgomery, St. Louis Cardinals

The Change: +23% Four-Seam, -11% Sinker
Montgomery didn’t use his four-seamer very often in New York, and it’s not hard to see why. It looks like a four-seamer thrown by a sinkerballer; it has more run than a true four-seam fastball, and falls three inches more than average on its path homeward. That sounds like an awful pitch to throw when you have access to Montgomery’s superb sinker, but he’s leaning on it as his primary pitch in St. Louis.

Why? He told Katie Woo of The Athletic that Yadier Molina has called a lot of glove-side fastballs higher in the strike zone. When he throws glove side and high, he does it with a four-seamer instead of a sinker. That makes sense to me mechanically; his sinker has a huge amount of arm-side run, which makes commanding it to the glove side problematic.

I suppose I can buy that argument as long as I don’t think about it too hard. Montgomery has been downright surgical with the pitch since donning the birds-on-bat uniform; he’s located 47.4% of his four-seamers in the shadow zone, the fringes of the plate where batters have no good options, an 80th-percentile mark, while leaving the pitch over the heart of the plate only 26.6% of the time (75th percentile, where higher is better for the pitcher).

Still, color me skeptical. The pitch gets less movement, and in a less interesting direction, than his sinker. It’s not like he can’t locate the sinker, either: he has hit the corners more frequently with that pitch as a Cardinal. The four-seamer has worked so far, but it’s a tightrope act of a pitch; without good location, it’s inarguably below average. The Cardinals have the best infield defense in the game, so pitching to that should be a priority. In fairness, Montgomery has gotten a ton of grounders with his four-seamer so far this year, and he’s been particularly adept with it since his trade, but it still generates fewer grounders than his sinker.

If you’re intent on coming up with excuses, there are always ways to justify the change. Maybe St. Louis’ pitching philosophy relies on glove-side fastballs from lefties and Montgomery simply can’t throw that pitch as a sinker. Maybe his fastball naturally turns looks four-seamer-ish when he throws it to his glove side, à la Max Fried. But c’mon. Throw your best pitch more often, not less.

Location isn’t worthless or anything, but think about it logically. Montgomery’s sinker is objectively hard to hit, no matter where he places it. His four-seamer draws most of its value from painting corners. But no one this side of peak Greg Maddux can hit the corner every time. Location is probabilistic, far more so than stuff. Montgomery might have seen success by leaning into a pitch he can throw to one side of the plate, but you don’t need to be an ambi-turner to succeed in the majors. Just ask Jacob deGrom.

Noah Syndergaard, Philadelphia Phillies

The Change: -16% Four-Seam, -9% Changeup, +13% Sinker, +7% Slider
Syndergaard might be best known as a fireballer, but his current form is nothing like that. At 94 mph, his fastball is hardly overpowering, and its shape does it no favors; it wouldn’t be fair to call it a terrible pitch, but it’s certainly below average.

Syndergaard had already used his sinker more this year, but he’s doubled down on that shift with the Phillies. I think this is an unequivocally positive change; it looks to me like a roughly average pitch, which gives it a leg up on his four-seam. If you aren’t going to blow people away with a fastball these days, you might as well limit damage on contact.

More importantly, Syndergaard has both increased his slider usage and changed the pitch meaningfully. Pitching coach Caleb Cotham worked with him to regain some of the fearsome velocity he showed in his halcyon New York days, and he’s added three ticks to the pitch; it now clocks in at 86.5 mph on average. That’s cost him a few inches of horizontal movement, but that was never really Syndergaard’s game anyway; he’s always succeeded through tunneling and velocity with the pitch.

The results have been promising, though it’s too soon to tell how the experiment will turn out. His swinging strike rate with the slider has gone down, but he’s achieved better results on contact. However things go, though, I’m a fan of what Syndergaard and Cotham are trying. The erstwhile god of thunder was at his best with a hard slider. Why not see if he can recover his hammer?

Tyler Mahle, Minnesota Twins

The Change: – 11% Slider, +12% Cutter
This is a more nuanced change than the two previous ones, and it’s certainly possible that Mahle’s cutter and slider blend together in pitch identification systems. He’s also been limited to four starts since joining the Twins thanks to injury problems, so the picture is even muddier. But the basics of this change make sense to me.

Mahle’s slider has always been more show-me pitch than put-away weapon. It’s in the uncanny slider valley; not enough velocity to generate poor swing decisions via rushing hitters, and not enough movement to make hitters miss after they commit to swinging. This year, Mahle had started experimenting with splitting the two, throwing a harder cutter and softer slider that move differently.

I don’t think either pitch is great, and I assume Mahle doesn’t either. He relies on a four-seam/splitter combination to get the job done, and both pitches are above average. Still, he needs something that moves arm side to vary his looks. Mixing up the slider and cutter didn’t seem to do much, so upon moving to Minnesota, Mahle went almost exclusively to the harder pitch. I’m not sure it matters too much. I’m not even sure it’s a “real” pitch change; this year’s cutter is quite close to last year’s slider in terms of velocity and movement. Consider this a lateral move: Mahle discarded his slower breaking ball and went back to the harder one exclusively.

Tucker Davidson, Los Angeles Angels

The Change: -6% Four-Seamer, -7% Curve, +7% Changeup
Davidson was the part of the Angels’ return in the trade that sent Raisel Iglesias to Atlanta. He’s more innings-eater than anything else; his ERA with both squads so far this year is above 6.00, though his minor league numbers suggest better performance might lie ahead.

To that end, he’s been tinkering with his changeup. It was an afterthought in limited action with the Braves; he threw it less than 1% of the time, essentially never. He’s thrown 38 changeups this year, and 36 of them have come with the Angels. The early returns have been good: though Davidson has been replacement level with the team, his changeup hasn’t been the problem.

That doesn’t mean I expect the good times to continue. It’s not a particularly great changeup; he simply doesn’t kill enough spin to give the pitch the strong downward movement it needs to succeed. It’s more average than exciting, and to make matters worse, he doesn’t have great feel for it. He both leaves an above-average number of changeups over the middle of the plate and misses the zone by too much to entice hitters more often than league average. That’s hardly surprising; after all, it’s not like the Angels are the first team to realize that lefty starters often throw changeups. The fact that Davidson hasn’t thrown a changeup before now is a solid indication that he doesn’t have a particularly good one.

I still think that Davidson should stick with the pitch. The path to success in the majors as a soft-tossing lefty with no changeup is vanishingly narrow. Just because he doesn’t have a good one right now doesn’t mean he shouldn’t try to develop one. Sometimes a new pitching coach, or a new set of teammates, can lead to a new grip or increased comfort with an old one. Particularly given the Angels’ position in the standings, a little pain now could mean gain down the road.