Before the 2013 season, Jarred Cosart was the 50th-ranked prospect by Baseball America and the 89th-ranked prospect by MLB.com. That season, he was promoted to the majors, started 10 games there, and posted a 1.95 ERA and 4.35 FIP. His game was fraught with errors however, including having walked more guys than he struck out in those starts. In 2014, the walk and strikeout problems persisted and Cosart struggled again this year, though he retained his ability to get ground balls and limit the home run.
In 2013, the Marlins drafted Colin Moran with the sixth pick of the MLB draft, and he immediately went to Low-A Greensboro. He played decently there, batting .299/.354/.442, which was 27 percent better than the league average. He was ranked as a consensus top-100 prospect, ranking 61st by Baseball America and 51st by MLB.com. But he had a rough time in the Arizona Fall League in the offseason, and this year his power is down drastically in High-A Jupiter and his batting line of .294/.342/.393 is only 12 percent better than the league average mark.
Yesterday's trade between the Miami Marlins and Houston Astros represents a bet on the Marlins' side. The Marlins are betting that Cosart's future as a former top prospect is brighter now that he's survived 173 innings in the majors than Moran's. But is that a good bet?
Jarred Cosart is not without his warts. He has 108 career strikeouts and 86 career walks in those 173 innings, so his strikeout-to-walk rate is still atrocious. He has an awful time missing bats, with just a six percent swinging strike rate over the course of his young Major League career. His stuff includes a 94 mph fastball that is of the cutter or four-seam variety, a developing curveball as a secondary pitch, and a mix of changeup and slider for poor tertiary offerings. In a sense, his pitches sound a lot like Nathan Eovaldi's, and that matches up with Eovaldi's issues with getting swings and misses as well. Cosart has a worse situation in that even his secondary pitch is not effective at whiffs; the curveball has just a 20.5 percent whiff rate thus far in his career.
It would be better if Cosart threw the ball in the strike zone more often, but he does not do that like Eovaldi. His 46 percent career zone percentage fits the profile of a player like Jacob Turner more than Eovaldi. But unlike Turner, who had issues with strikeouts in the minors too, Cosart never displayed average or better swinging strike rates in the majors. Even in 2014, Turner has at least a 9.0 percent swinging strike rate.
So Cosart's problems are that he allows too much contact and walks too many guys. In a sense, his "warts" are the worst of both Eovaldi's and Turner's games.
On the Ground
If that's the case, why acquire him at all? To start, Cosart does have tantalizing stuff. His cutter is the highlight of his approach. It runs almost 95 mph, excels at getting ground balls, and is his only pitch that he can reliably throw in the strike zone. The 55.6 percent ground ball rate over the course of his career is a huge boon to his ability to keep the ball in the park. Overall, the cutter has been worth 1.36 runs above average per 100 pitches over the course of Cosart's career thus far.
But his cutter is not the only pitch that gets hitters to hit worm-burners. The curveball's only strong suit thus far is its own ability to get grounders. Cosart has gotten grounders on 61 percent of balls in play on the curve, which is unusual and speaks to the location of the pitch.
All told, Cosart's 56 percent career ground ball rate is impressive and allows him to avoid homers. But he also has shown at least one year's worth of ability to naturally avoid the home run, as he owns a 7.2 percent home run per fly ball (HR/FB) rate. All of that, combined with the natural effect of Marlins Park's dimensions, should lead to extreme home run prevention from Cosart, which may be his strongest suit in Miami. In a way, he takes the best aspect of Henderson Alvarez's game and amplifies it.
So what is Cosart going forward, and is it better than Moran? Clearly, the Marlins wanted help immediately, which is why Moran was dealt to supplement the present. But Cosart will be here until 2020 if he stays under his full term of team control, and he is only one year removed from being a top prospect. There are enough question marks in his game that the Fish should be concerned about him as a starter, however. Right now, he is projected to post a 4.22 ERA and pretty similar FIP. That projection by ZiPS expects an increase in both strikeouts and walks and some regression on that home run total.
Where Cosart can improve is his walk rate. Alvarez has already shown that you can be a successful groundballler if you avoid the walk and keep getting them to hit it into the arms of the infield. Miami's infield isn't spectacular defensively, but it is good enough that it should soak up a decent number of Cosart's grounders. Keeping the ball in the park at the rate he has so far can go a long way to maintaining success, but he has to do it with fewer baserunners on board. That minimizes the desperate need for increased strikeouts and lightens the pressure on Cosart developing a knockout second or third pitch.
Four of the Marlins' five expected starters this season pound the strike zone with impunity, and that is the reason behind their relative success. If Cosart can pick that up, he can probably develop into a league-average starter, which is great under team control. Moran likely will not be a league average player for another two seasons, so Miami can get a head start on solid production with this trade. But since Cosart has not developed those skills yet, we still cannot be sure. RIght now, he is projected to be a one-win pitcher per season, which is about a half-win upgrade over the Brad Hand and Jacob Turner types.
Miami made this trade for immediate production, but it was betting on a better future in Cosart. If he can harness the strike zone better, they may get it, but right now, this trade is only a small increase in production.