Two months of the season. More than a third of the total regular-season baseball we’ll get this year. That’s enough games for a pitcher to have done something one way, then changed it up and given us a large enough sample to see that something is truly different now.So, which pitchers have made changes over the last month, and given us a second act that might preview a grand finale?Here are the starting pitchers who have changed their Stuff+ the most over the last 30 days, when compared to April numbers.
Biggest Stuff+ improvers NameLast 30 Stuff+April Stuff+Diff S+Emmet Sheehan1059114Sean Burke100928Noah Cameron98917Justin Wrobleski98917Roki Sasaki1091027Aaron Nola1101046Andrew Abbott98926Tomoyuki Sugano84795George Kirby104995Michael King98935
It’s nice when the process stats line up with a complete change in results, as they have with Roki Sasaki. His move to a harder splitter in favor of the forkball has given him more in-zone options and pushed his strikeout minus walk rate from terrible to elite in a four-start stretch. Finding another tick on the fastball has to be part of the story, but for the entire perspective, read Fabian Ardaya’s excellent piece on the subject.Some of these pitchers, like Tomoyuki Sugano and Michael McGreevy (not in the table, but he had a +3 Stuff+ jump), didn’t have great stuff to begin with. They survive by throwing wide pitch mixes with decent command. But a few of these names are intriguing enough to highlight on their own.Aaron Nola, RHP, Philadelphia PhilliesThough some of the stuff numbers have changed, Nola’s process stats remain remarkably similar to those he was putting up in the first month. He had a 15.7 percent strikeout minus walk rate in the first month, and it was 15.2 percent in the second month. His SIERA was high 3s both months. And his ERA in any month has been terrible.Can Phillies fans and wannabe Nola buy-lowers take heart in the improving Stuff+ numbers? Maybe not.The good news is that, before his last start, he’d been steadily improving his velocity. From the doldrums of the 91 mphs early in the season, he’d pushed his fastball up to the high 92s and even had a start at 93.4 against the Padres. With the average right-handed starter averaging close 95 on the fastball, that’s still not great, but it’s better. His curveball added a little drop, his fastball a little ride and everything was a little crisper in May than it was in April.The problem right now seems to be lefties, though. He’s allowing a .311/.396/.515 line against them that is both untenable and part of a five-year trend in the wrong direction. And when you look at his Stuff+ versus lefties, set against the results on those pitches, the problem becomes pretty clear.
