The Mets’ best rotation probably includes Robert Gsellman over Zack Wheeler

With spring training having just gotten underway, the Mets are understandably excited about the chance of opening the season with all five of their big-name starting pitchers healthy. Those five—Noah Syndergaard, Jacob deGrom, Matt Harvey, Steven Matz, and Zack Wheeler—have never been in the rotation at the same time. But there’s at least a chance that Wheeler is not the Mets’ best option for the last spot in the rotation, a spot that Terry Collins said he views as an open competition.

To the Mets’ manager, Wheeler has a chance at earning that role along with Robert Gsellman and Seth Lugo, both of whom excelled at the major league level in relatively brief stints last year. In reality, all three pitchers will likely spend at least some time in the rotation, either to account for injuries or simply to spread the workload of baseball’s long season around. But in the hypothetical scenario that everyone’s completely healthy and unrestricted, Gsellman might be the best bet for the Mets to find success with the final spot in their rotation.

Two years ago, finding out what Wheeler would do in his third full season in the big leagues was downright exciting. At the time, deGrom was coming off his Rookie of the Year season, Harvey was set to return from his own Tommy John surgery, and both Noah Syndergaard and Steven Matz looked like they’d be knocking on the major league door in short order. Wheeler had ended his 2014 season strong, as he had a 2.93 ERA over his final eighteen starts, the first of which was the shutout he threw against the Marlins in Miami.

In total, Wheeler has 49 major league starts to his name with a 3.50 ERA and 3.77 FIP. ERA-, which rates performance relative to league and park, has him at 100—exactly league average. It’s clear that Wheeler was an established major league starting pitcher before his Tommy John surgery, but its’ tough to assume he can pick up right where he left off—or improve upon that level of performance—after such a long layoff.

Gsellman doesn’t have nearly as much major league experience, but what he did in his time with the Mets was awfully impressive. With better stuff than anyone expected, he racked up a 2.42 ERA and 2.63 FIP in 44.2 innings with a 61 ERA- that put him well aboe average. Lugo had a 2.67 ERA in 64.0 innings last year, though his 4.33 FIP makes the sustainability of that look a little more suspect, but like Gsellman, he compared to his peers pretty well with his 67 ERA-.

The projections don’t love Gsellman as much as, say, the Baseball Prospectus list of the game’s top 101 prospects for this year. Here’s how the three pitchers compare in terms of ERA projections from ZiPS, Steamer, and PECOTA:

If we’ve learned anything over the past few years, it’s that keeping a group of pitchers healthy all at once is hard to do. Even a variety of minor injuries could derail the larger plan to have a five-aces rotation, and this sort of rotation logjam could sort itself out without the Mets having to make any tough choices.

But if all goes well in that regard, Gsellman might be the guy who belongs in the top five. The projections don’t buy what he did with the Mets last year and paint a pretty rosy picture for Wheeler’s return. But if Gsellman pitches like he did last year, even with slightly worse results, he’d pretty clearly be the best starting pitcher of the three vying for that last spot in the rotation.