For all the hair-pulling that fans have done over the Mariners’ seeming unwillingness to spend money to upgrade the starting rotation, there has been one panacea: James Paxton. The 2017 season sucked monkey butt, but every fifth day fans had the comfort of Big Maple, the fun of the Maple Grove, and the satisfaction of knowing one of the best starting pitchers in the game belonged to the Mariners.
However, so far in 2018, the de facto ace of the Mariners’ rotation hasn’t seen a return to the dominance he showed at his best in 2017. Coming into his start against Cleveland, he was sporting a 5.61 ERA, and even his FIP of 4 was well above the 2.61 he posted last year. It’s early yet, but Pax has also lost over 10% off his groundball rate while seeing his flyball rate spike. His strikeouts are up, but so are his walks, and his home run rate has already more than doubled where he was last year. Most troublingly, Paxton has had trouble getting deep into games, averaging just a hair over five innings per start, and has failed to clear the fourth inning twice in five starts.
Part of the reason Pax has had trouble getting deep into games is his pitch count. Pax has thrown about as many pitches as other starting pitchers like Max Scherzer, Justin Verlander, and Clayton Kershaw, but he’s thrown about ten innings fewer than any of those guys. Paxton is still throwing hard, with no noticeable decline on his fastball velocity, so why isn’t he being more efficient with his pitches?
Part of the answer could be in the way the zone is being called this season. Among players with at least 50 called strikes and at least 100 pitches thrown, Paxton ranks near the lowest end for percentage of total pitches that have been called strikes. Sharing space with him at the bottom of the list: Kevin Gausman, Trevor Richards, Steven Brault—all pitchers who favor the bottom of the zone. With the exception of Corey Kluber, the pitchers at the top of the leaderboard for called strikes split the majority of their offerings between higher in the zone and targeted spots in the bottom of the zone.
Paxton has had about 14.6% of his pitches called strikes this year. This is his zone profile:
For comparison, fellow lefty Steven Matz has had over 22% of his pitches called for strikes:
So perhaps there is a shift across baseball where the low strike is becoming more elusive; MLB has threatened to raise the strike zone, as Manfred continues to wage his one-man war against the sport of which he is the commissioner. The other part of this, obviously, is that Paxton has been pitching without the aid of Mike Zunino behind the dish. Because of Zuninus Interruptus in 2017 and the oblique injury of 2018, the catcher split sample size for those years is pretty small, but in 2016, in about equal numbers of innings, Paxton’s ERA was a full run lower when Mike Zunino caught him rather than Chris Iannetta, with a significantly lower slash line.
Any pitcher can benefit from Z’s superb framing, but Paxton especially is helped out by Z’s ability to handle high-velocity pitches at the bottom of the zone without jerking them. Not many catchers could handle this pitch at 98 and not only not have the downward momentum drag their hands down, but in fact be able to fight the pitch back up into the zone:
We usually talk about Mike Zunino’s strength in context of his bat, but these beefy forearms are useful behind the dish as well:
The Zunino effect wasn’t able to help Paxton out during a poor start in Texas where he didn’t have command over his secondary pitches, but he was able to steer Big Maple through six solid innings against Cleveland, where Paxton wobbled initially with the curveball before being able to spot it for strikes. Even with the Zunino bump, if the zone is shrinking upwards, commanding all his pitches early to earn an expansive zone will be the key to Paxton getting deeper into games and re-establishing his ace status.