Nathan Eovaldi, Jarred Cosart and Misreading Statistics


Coming into the 2014-2015 off-season, the Miami Marlins had pitching depth that was the envy of the league. The team had a strong rotation, top left handed pitching prospect before the season in Andrew Heaney, and a solid prospect pitching base. The plan was to fill the question marks around the infield with that pitching depth.

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Heading into the new year, the Marlins have a brand spanking new infield, with three of the four positions being manned by players that didn’t have the home run sculpture go off when they hit a home run (not that Dee Gordon hits many of those). However, the team’s pitching depth that was the envy of the league is now almost completely depleted.

To acquire Dee Gordon, Martin Prado, and Mat Latos, the Marlins had to part ways with Nathan Eovaldi, Anthony DeSclafani, and Andrew Heaney. DeSclafani and Heaney were considered the top two Marlins prospects by many experts. While both are extremely talented, both were seen as expendable to help the Marlins improve. Though an argument could be made that the Marlins could have gotten a better upgrade for Heaney, but that’s a different story.

While the consensus for Marlins fans that trading Eovaldi for Martin Prado improved the ballclub, the trade in actuality was a wash, as the Marlins rotation got weaker, though their third base position improved, as Eovaldi to Phelps is a 1-2 win downgrade and Prado over McGehee is a 1-2 win upgrade.

Eovaldi is a player that the Marlins dealt that could really come back and haunt them, this season and beyond. As Michael Jong points out on Fishstripes, the Marlins have done a poor job of analyzing Nathan Eovaldi and the rest of the team’s pitching.

"The problem is that the Marlins are not using all the information. They are not looking at Eovaldi’s strong trends in walk rate. They are ignoring the fact that, over the last three years, he has upped his strikeout rates to acceptable levels. They ignored Cosart’s poor performance in 2013, when he walked more guys than he struck out. They saw his shiny ERA, especially in the first month, and ignored that his numbers fell back the following month to his typical levels. You can bet that the Marlins’ brass has strongly ignored the numbers that predict future performance better and relied rather strongly on cursory glances at ERA and their own scouting judgments."

As Michael points out in his article, the Marlins for some odd reason have made Jarred Cosart untouchable, based on one strong month of pitching. They soured on Eovaldi in that time, despite trends in Eovaldi’s numbers that suggest he’s going to get better.

I have heard a lot of “Cosart is more consistent” comments coming from Marlins fans, though that cannot be further from the truth. Eovaldi’s peripherals numbers have been better and more consistent than Cosart’s, even in 2014:

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That first month Cosart spent with the Marlins that left such an impression with the fans and the team, it was more than likely a fluke. The walks that he was giving away in Houston somehow were cut in half, but magically more than doubled, back near his career rates, again in the month of September, though he did find more of strikeout groove in September.

Despite the uptick in strikeouts, September had Cosart closer to a league average pitcher that a top of the rotation arm. In fact, Cosart’s K%, FIP, and xFIP in September were closer to his career norms than his August numbers.

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The only consistency in his numbers between the two months would be his ground ball percentage. So headed into his first full season as a Marlin in 2014, we still don’t know what kind of pitcher the Marlins have in Cosart.

Eovaldi, meanwhile, had a stronger August than Cosart did. His peripheral numbers were superior to Cosart’s, but his overall line was brought down by his .359 BABIP, which was actually a full 100 points higher than Cosart’s and 50 points above his career mark of 3.09.

While Eovaldi did have a down month of September, his overall numbers, besides the ERA, stat, were actually better than Cosart’s once again. Cosart did strikeout 2% more hitters, but Eovaldi walked 5% less for the month. Eovaldi also had a better groundball percentage in the month of September than Cosart.

So while the Marlins value Cosart higher than Eovaldi, the two are actually closer than the Marlins would like to imagine, with Eovaldi likely the better pitcher. The Marlins actually sold low on Nathan Eovaldi instead of selling high on Jarred Cosart.

Next: Marlins Sign Vinny Rottino