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Trevor Cahill has made a comeback

The Padres rotation still sucks — but it sucks a little bit less now.

MLB: San Diego Padres at Los Angeles Dodgers
Sample size, schmample size. It’s April, and Padres fans need something to be optimistic about.
Kirby Lee-USA TODAY Sports

Let’s play some word association. When I say “Mike Trout,” the first word that comes to your mind is probably “superstar,” “wunderkind,” or something to that effect. When I say “Giancarlo Stanton,” you probably think of “hulk,” “masher,” or another moniker that reflects his power. And at the words “Padres rotation,” your reaction is probably…well, not the sort of thing I can reprint here.

Back in December, when FanGraphs released its ZiPS projections, Carson Cistulli noted that the Padres’ starters were a historically uninspiring bunch. Since then, San Diego has brought in Jered Weaver, Jhoulys Chacin, Clayton Richard, and Trevor Cahill — a motley crew of washed-up hurlers. FanGraphs projects the Padres rotation to finish 29th in the majors in fWAR, leading only the Reds; given how well Brandon Finnegan and Scott Feldman have pitched thus far, I’d swap those two clubs in the hierarchy.

But while the Padres rotation is horrendous as a whole, one starter has fared exceptionally well thus far. Against two pedestrian offenses (the Marlins and Braves) and an elite one (the Dodgers), Cahill has looked like his old self. Actually, he’s looked even better — he’s struck out 28.9 percent of the batters he’s faced, while racking up a 60.0 percent ground ball rate. (He’s also notched a 9.5 percent walk rate, but with that many Ks and grounders, a few free passes won’t hurt him.) That’s resulted in a 3.44 ERA and 3.33 FIP, both of which would be much lower with a normal HR/FB rate.

Across the board, Cahill’s peripherals have improved. His swinging-strike rate has surged to 14.9 percent, the highest of his career. During 2009 to 2013 — his five full seasons as a starter, before becoming a swingman in 2014 — he never came close to that over three games:

Image via FanGraphs

Cahill’s also gotten a 37.9 percent O-Swing rate (the highest of his career) and a 52.9 percent Z-Swing rate (the lowest of his career). This is unprecedented territory for him all around.

Of course, Cahill’s been a sneaky-good pitcher for a couple of years now. FanGraphs’s Owen Watson explained back in 2015 how Cahill had changed his fortunes — he moved to the bullpen, tweaked his delivery, and significantly improved his curveball and changeup. This year, each of those offerings has a whiff rate above 20 percent, in addition to a ground ball rate of at least 50 percent. With secondary pitches like that, Cahill’s made the transition back to starting pretty smoothly.

Still, even as a reliever, Cahill wasn’t this dominant. Something about his arsenal is different this year. As he worked his way back into the rotation, Cahill began experimenting with a new pitch:

Seeking to start again, Cahill has begun to reincorporate a fourth pitch, the cutter. The sinkerballer estimated he threw four Tuesday, compared to one all of last season.

“It functions well, in my mind, against certain left-handed hitters, just to get in on hands of guys that sit out over very well,” Green said. “It’s a pitch that at the right time can be deployed against the right hitter.”

Brooks classifies the pitch as a slider, but whatever you call it, Cahill’s definitely started to throw it more often:

Image via Brooks Baseball

This season, the average right-handed starter has thrown a slider at 85.6 mph, with 2.6 inches of horizontal movement and 2.7 inches of vertical movement. Cahill’s slider is at 86.2 mph (so a little bit harder), 0.3 inches (so a little bit less run), and 0.9 inches (so a little bit more drop), respectively.

The result? A power breaking ball that dives like crazy, leaving hitters flailing:

GIF via

To get this out of the way once: Cahill has thrown his slider 31 times this year. That’s a small sample size. With that said, in those 31 appearances, the slider has gotten 10 whiffs, and has gone for a ground ball all three times it’s been put in play. A 32.3 percent whiff rate on the slider would have been the best among all starters last year* (Noah Syndergaard’s slider led the way, at 28.6 percent); obviously, the same goes for a 100 percent ground ball rate.

*Among those with at least 200 sliders.

Cahill still relies on his sinker more than anything else — he’s a sinker-baller first and foremost. But with his slider in his back pocket, he doesn’t need to use the sinker as often, and he hasn’t: He’s thrown the pitch 36.1 percent of the time this year, more than 17 percentage points below his career average. The new, quasi-junkballer version of Cahill has four legitimate pitches, and thus far they’ve made him a top-notch starter.

The Padres, in fairness, are on the upswing. GM A.J. Preller has assembled one of the most formidable farm systems in baseball, and this team has some talented youth, from Wil Myers to Ryan Schimpf to Brad Hand. Despite having pitched for what feels like forever, Cahill is still just 29, so he has something left in the tank. Whether the team trades him or keeps him around, his rediscovered slider — and the excellence that it’s brought — should give Padres fans something to look forward to every fifth day.

All data as of Saturday, April 23.

Ryan Romano is the co-managing editor for Beyond the Box Score. He also writes about the Orioles for Camden Depot, sometimes. Follow him on Twitter if you enjoy angry tweets about Maryland sports.