Dreaming on Jarred Cosart

When I first read that the Padres acquired Jarred Cosart from the Marlins as part of the Andrew Cashner trade, gotta admit, I wasn’t too thrilled. I liked the overall return—even with Luis Castillo and Colin Rea now switching sides—but Cosart felt like a throw-in, at best, a backend starter if everything works out and bullpen fodder if it doesn’t. In researching the right hander more for a Transaction Analysis at BP, I discovered that Cosart’s no. 10 PECOTA comp is Zach Britton. Color me intrigued.

Of course, reading too much into one comp is exactly what you’re not supposed to do. PECOTA uses many comps, for a reason, and drawing conclusions from a single one while ignoring the rest is an irresponsible use of information. Color me irresponsible. Consider this comparison between the two pitchers:

Pitcher Starts ERA, cFIP K:BB ratio GB%
Britton, 2011-2013 46 4.86, 101 1.49 57%
Cosart, 2013-2016 57 3.68, 111 1.32 56%

Britton, a lefty, was a complete disaster in Baltimore’s rotation. In his first three years in the big leagues, there were almost no tangible signs* that he could turn into a successful major-league pitcher. Then, out of desperation, the Orioles turned him into a reliever in 2014, and since then Britton has developed into one of the most devastating relief aces in the league. He’s going on his second straight sub-2.00 FIP season while his groundball rate, solid enough as a starter, has spiked to an almost unthinkable 81 percent since 2015. There are plenty of cases of bad-to-mediocre starters turning into successful relievers, but Britton is one of the most extreme examples, transformed from a replacement-level starter to an irreplaceable reliever in a single offseason.

*Okay, the cFIP offered some hope.

Watching parts of Cosart’s first Padres start last night—3 1/3, 1 hit, 0 runs, 6 walks, 3 strikeouts—I couldn’t help but wonder when the shift to the ‘pen was going to happen. (Did it happen yet?) There were positive signs—the stuff looked good at times, the delivery had some deception, and, outside of the first inning, Cosart kept the ball on the ground, including two double-play balls. But the control was off, obviously, and Cosart didn’t look like the type of pitcher who’s going to run through a lineup, with success, multiples times.

Back to Britton:


Look at what happened to his sinker velocity once he entered the ‘pen. It went up from 92-93 as a starter to 96-97 as a reliever, and it’s still trending upward. Undoubtedly, that kind of velocity jump explains, at least in part, why Britton has been able to ramp up his ground ball rate by over 20 percent and his strikeout rate by 15 percent. Although Britton is somewhat of an outlier, even the average pitcher sees a velocity gain of about a mph, or so, when pitching out of relief as opposed to starting. Cosart’s cutter, his primary offering according to Brooks Baseball, already registers at nearly 95 mph, so with a successful switch to the bullpen, he could turn into a high-90s type.

The Padres don’t have anything to lose this year, so perhaps it makes sense to audition Cosart as a starter—after all, you’d probably rather have a league-average starter over a shut-down reliever, save for a Britton type. Cosart might have the stuff and prospect pedigree to warrant a longer look in the rotation, not to mention—since we’re talking about comps—that Chris Archer and Garrett Richards also show up on his top-10 PECOTA comp list (Tyson Ross is no. 11). But if the starting thing doesn’t click, the Padres shouldn’t give Cosart the Cashner treatment. Instead, they should just send him to the bullpen and pray for Britton.

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