This is Jake Mailhot’s third post as part of his May Residency at FanGraphs. A lifelong Mariners fan, Jake now lives in Bellingham, Washington, just a little too far away from Seattle to make it to games regularly, which is sometimes for the best. He is a staff editor at Mariners blog Lookout Landing. He can be found on Twitter at @jakemailhot.

Earlier this year, Jeff Sullivan wrote a pair of articles, each about a pitcher who appeared to be McCullersing. That term, of course, is a reference to Lance McCullersJr., who in 2016 began throwing his excellent curveball more often than his fastball. He’s led all of baseball in curveball usage since then. He wound up throwing his curveball an astonishing 75% of the time in Game Seven of the ALCS last postseason. That appearance was peak McCullersing.

He started off this year throwing his curveball around the same amount as last year, 48% of the time. But when the calendar flipped to May, something changed. Just look at this graph of his secondary pitch usage in 2018.

That’s… interesting. In his start last night (not included here), McCullers threw his curveball around 40% of the time. That’s pretty normal for him. But it’s been less normal for him of late. In his start against the Angels last Monday, McCullers actually threw more changeups than curveballs, the latter pitch representing just 21.4% of his total count for the night. The last time his curveball usage fell below 30% was all the way back on August 3, 2015, during his rookie year.

Maybe we should have known this was coming. McCullers himself stated on multiple occasions this offseason that his changeup would be a point of emphasis for him during spring training. During the annual Astros FanFest, he laid it all out:

“I really want to get my changeup back to where it was last year in the first half. In the first half my changeup was an awesome pitch for me. I was throwing it a lot. Some games I would throw 20 to 25 of them. When I went on the DL for my back I kind of lost the feel for it and I never really got to get back to that.”

Last year, McCullers threw his changeup around 12% of the time, a pretty sizable increase over how he was using it in 2016. But in his four starts in May of this year, he’s thrown it over 20% of the time in each of them. He’s surpassed 20% usage a few times in his career, but those spikes never trended so clearly.

But McCullers isn’t just messing with his pitch mix again. He actually lost the feel for his curveball for a period earlier this season. After his start last Monday, he commented on how those struggles led him to revisit his changeup:

“I think as frustrating as it is not to have my best curveball, it’s forced me to develop a really plus-plus changeup. That is going to be good moving forward, going to be good in my career and I just have to keep with it, stay positive.”

Because his curveball is so outstanding, his changeup has always been an afterthought. But during his career, he’s generated a whiff around a third of the time a batter swings at his changeup. And when batters do make contact, they put it on the ground more than half the time. Both of those marks are better than the average changeup, making it pretty effective.

As he’s regained his feel for the pitch, the shape of it has actually changed. It seems as though tinkering with the pitch and getting comfortable with it again has made it even more exceptional. Below is a table showing the primary characteristics of the pitch during his four-year career, with z-scores comparing each component of it to an average changeup.

Lance McCullers’ Changeup, 2015-18 Year Velo Spin Rate H Move V Move 2015 89.8 (1.95) –* -8.04 (0.24) 2.45 (1.14) 2016 88.8 (1.57) 1901 (0.56) -7.54 (-0.06) 1.07 (1.78) 2017 89.3 (1.77) 1885 (0.49) -9.14 (0.89) 1.99 (1.35) 2018 87.8 (1.20) 1887 (0.50) -10.22 (1.53) 0.93 (1.85) SOURCE: PITCHf/x, Statcast *Statcast data not available for 2015.

McCullers has always had good sink on his changeup, likely the reason why he’s been able to induce such high ground ball rates with the pitch. But the last two years, he’s increased the horizontal movement of the pitch exponentially. It now has the eighth-most horizontal movement of any changeup thrown at least 100 times this season. He’s also throwing it slower than he has in years past. A larger velocity differential between his changeup and his fastball is definitely a good thing.

These changes to the raw characteristics of the pitch have made it more effective than ever. He’s increased his whiff-per-swing rate to 45.6%, the third-highest mark for a changeup among starters who’ve thrown the pitch 50 times or more. He’s still inducing contact on the ground half the time, but batters are having a particularly difficult time squaring up the pitch. He’s allowed just three hits off his changeup this year, none of them more damaging than a single.

A reliable third pitch should help McCullers navigate the opposing batting order later in the game. He’s really struggled when facing a lineup three or more times during his career. For the first two trips through the batting order, McCullers has posted an ERA of 2.97. That balloons to 5.50 when facing the order three or more times. In his four starts in May since reintroducing his changeup, McCullers has allowed just one run when facing the batting order the third time through (1.59 ERA).

Beyond that, McCullers has always been plagued by repeated injury trouble. It’s certainly possible that throwing so many curveballs was at the root of some of those injuries. By regaining the feel for his changeup this season, McCullers has added a reliable third pitch to his arsenal. If he continues to throw his bender a little less than his norm and throws his changeup a little more often, that could be the precursor to a completely healthy season for McCullers. It certainly helps that his changeup is a true weapon and has only gotten better this year.