JUPITER, Fla. -- The unorthodoxy of the Mets' fifth starter competition makes it difficult to gauge. One candidate for that job, Seth Lugo, is doing his best work miles away at the World Baseball Classic. Another, Zack Wheeler, has only recently begun pitching in games due to a cautious spring progression.
Then there is Robert Gsellman, who brightened his resume with five innings of one-run ball in Saturday's 5-4 win against the Cardinals. Striking out three and walking one, Gsellman lowered his Grapefruit League ERA to 2.65 in four starts. Of the Mets' three fifth starter candidates, Gsellman was the most successful in 2016. He has also been the most successful this spring.
"He has no fear," manager Terry Collins said. "This kid's not afraid of anything in any situation. He knows what he can do and he goes out and does it. He knows he can throw strikes. He knows he's got a weapon that's hard to hit, and he uses it."
That weapon is Gsellman's mid-90s sinker, which he used liberally throughout Saturday's outing. The right-hander also flashed multiple breaking balls and a changeup, saying afterward that "I'm not ready yet, but I'm almost there."
The issue stems not from Gsellman, but from the Mets' multitude of other options. Facing the potent lineups of Venezuela and the United States in World Baseball Classic play, Lugo has gone 2-0 with a 2.45 ERA, allowing merely six hits in 11 innings. He also posted a 3.86 ERA in three Grapefruit League outings prior to leaving.
Wheeler has appeared in two spring games, his first big league action since undergoing Tommy John surgery in March 2015. And while his overall statistics -- a 6.23 ERA, three strikeouts and two walks in 4 1/3 innings -- don't jump off the page, Wheeler flashed 97 mph in his last start, tantalizing the Mets with images of his past form.
"You've got to be careful what you're seeing in March, but certainly Zack got our attention the other day," Collins said. "I can't wait to have him get back out there again. But as we get down toward the end, we'll take a look and we'll make what we think is the best call for the team and the organization."
Most likely, that means a rotation spot for Gsellman, who -- unlike Wheeler and his roughly 125-inning cap -- has no significant limit attached to him this season. For the Mets, the path of least resistance appears to be Gsellman in the rotation, Lugo in the bullpen and Wheeler in extended Spring Training, where he would have more time to work into form.
"I'm confident," Gsellman said. "At the end of the day, it's still their decision. I've just got to go out there and pitch and do my job."
But with 11 days and two full rotation turns left until camp breaks, the competition is far from complete.
"It's a great problem to have," Collins said. "We came into this camp knowing we had depth in the rotation. We didn't know where Zack was going to be, but we felt with the other four guys, and with Robert and Seth, we had some depth here. And they have stepped up and shown us that we weren't wrong."
Anthony DiComo has covered the Mets for MLB.com since 2008. Follow him on Twitter @AnthonyDiComo and Facebook, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.