WEST PALM BEACH, Fla. — In a sport stockpiled with analytical thinkers, Spencer Arrighetti is starting to stand out. He speaks like someone with far more service time than a player preparing for his second season: articulate about his methods and accepting of any blame they may deserve.
Arrighetti is a model for the modern game, devoted to data but not devoid of feel. Last season, he ascended from relative anonymity into the middle of an injury-riddled Houston Astros rotation, one of the rookie saviors of what could’ve been a star-crossed season.
Arrighetti’s arrival last April appeared ahead of schedule, forcing a cerebral pitcher into a crash course on a championship-contending club. He survived it with one of the sport’s worst four-seam fastballs, a fact he can’t run from but can try to contextualize and correct.
“I know it’s not bad,” Arrighetti said, “I know it’s really great, actually, when I throw it up in the zone.”
Too often last season, Arrighetti did not. Start there when pinpointing a problem Arrighetti is attempting to fix. Opponents slugged .516 and struck 26 extra-base hits against Arrighetti’s four-seamer, the pitch that comprised 40.6 percent of his arsenal.
Two well-performing breaking balls and a wicked cutter helped Arrighetti compensate, carrying him to a 4.53 ERA and 171 strikeouts across 145 innings. In two-strike counts, hitters whiffed 41.9 percent of the time against Arrighetti’s sweeper and 43.3 percent against his curveball. No pitch in Arrighetti’s arsenal had a higher run value than his cutter.
Baseball Savant defines run value as “the run impact of an event based on the runners on base, outs, ball and strike count.” Only five pitchers who threw at least 1,000 four-seam fastballs had a lower run value on the offering than Arrighetti’s minus-8 mark.
Arrighetti left far too many four-seamers down and in against right-handed hitters, who slugged .516 against the pitch. At its best, “left-handed hitters do struggle with it immensely when I get it up and away and right-handed hitters struggle with it when I get it up, period,” Arrighetti said.
Because Arrighetti releases the baseball from such a low arm angle — almost at his right hip — and averages 7.2 inches of extension in his delivery, hitters can perceive his pitches as being harder than the actual velocity he’s throwing. Arrighetti averaged just 94.1 mph on the 1,018 four-seamers he threw last season.
“Hitters go up there more aware that my (four-seam) is going to get on them quicker,” Arrighetti said. “So when I miss in a bad spot, it’s like their best friend. I did them the biggest favor ever by throwing them something straight down where they can drop the bat and elevate.”
At Arrighetti’s discretion, catchers are setting up higher this spring to encourage missing above the strike zone as opposed to anywhere down and in. As a result, Arrighetti has surrendered one hit against a four-seamer in his first six Grapefruit League innings.
“If I can do that, I think that really that’s it and that’s why I want to throw more fastballs that move,” Arrighetti said. “My (four-seamer) moves, like it runs in, but it doesn’t run in in a way that’s going to miss the bat, so that’s like the next step for me.”
To further it, Arrighetti is now throwing a two-seam fastball. Though it made sporadic appearances last season at the major-league level, Arrighetti has been refining it for three years.
Arrighetti acknowledged that throwing both types of fastballs is becoming “the next thing” in a copycat league, so it shouldn’t be a shock to see him try. That teammate Hunter Brown transformed his career by making a similar adjustment last season “piques your interest,” Arrighetti said.
“He wasn’t necessarily getting bad results on fastballs, but he was in a spot where a lot of hitters felt comfortable staying (on the inner half of the plate) and never moving,” Arrighetti said. “That’s not a great thing.”
“I feel like part of my game is making people as uncomfortable as I can, and if it adds to it, then that’s all the better for me. I feel like now I have three big movers both ways.”
Brown began throwing a sinker, in part, to induce softer contact early in counts and increase his pitch efficiency. That most of the damage against Arrighetti’s four-seamer came when he fell behind in counts only increases the potential value of a sinker. Hitters ahead in the count were 14-for-46 (.304) against Arrighetti’s four-seam fastball last season,
“When I have to be in-zone, that margin of error that was up here now shrinks,” Arrighetti said. “(The four-seam fastball) has got to be (thrown in the) upper third or else kind of thing. Having another pitch that I can throw that will move and maybe miss the bat in a better way, that’s what I have to do.”
(Photo: Jeff Roberson / Associated Press)
