PORT ST. LUCIE, Fla. -- When first asked about the Mets' rotation this offseason, new manager Mickey Callaway left things purposefully vague. Jacob deGrom and Noah Syndergaard, the Mets' twin aces, are of course guaranteed spots. After that? Callaway isn't saying.
Provided they are healthy, Matt Harvey and Steven Matz are strong bets to win jobs based upon their histories as successful big league starters. Beyond them, the Mets still have a number of pitchers -- Zack Wheeler, Robert Gsellman and Seth Lugo most notably -- vying for roles in New York's rotation. They also signed veteran left-hander Jason Vargas, who has made 228 Major League starts over a 12-year career, to a two-year contract on Friday, according to a source.
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It will be one of the few true position battles in Mets camp this spring. And it promises to be a good one.
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"I don't think we've seen them enough for me to really answer that question at this moment," Callaway said Tuesday during his first Spring Training news conference as Mets manager. "I think that guys know there's a battle coming and we have a lot of depth. I think all eight of our starters, or maybe even more than that, can contribute in the big leagues."
The Mets know what they have in deGrom, who set career highs in starts and innings last year, and Syndergaard, who was fully recovered from his right lat tear by late September. But they can't be certain about any of the others. Although Harvey also returned from injury at the end of last season, he was a shell of his former self, going 1-4 with an 11.28 ERA in six September outings. Matz, meanwhile, has not pitched since undergoing season-ending elbow surgery in August.

Even under the assumption that those two will earn roster spots, rounding out the Mets' rotation will not be an easy task for Callaway, new pitching coach Dave Eiland and the Mets' front office.
"We'll have a better sense of that obviously moving forward, and obviously we're going to have to make some kind of decision at some point," Callaway said. "The good part is from what I've seen so far, there's eight to 10 guys that are making that decision already hard on us. Dave and I are talking and we're like, 'Wow. This is a great group of arms that we're seeing.' That is a good, good problem for us to have, is to have to make some really difficult decisions when that decision time comes.

One option is Wheeler, not so long ago one of the top pitching prospects in baseball. Since undergoing Tommy John surgery in March 2015, Wheeler has made just 17 pedestrian starts in the big leagues. Because Wheeler is set to earn $1.9 million this season, the Mets have a vested interest in keeping him around -- at the very least in a bullpen role. But he has spent the past six months taking daily injections of bone growth medication in an effort to stay healthy, prompting worries that he may not be ready to endure a full season.
One of the prime contenders in last year's spring competition, Lugo remains a candidate after going 7-5 with a 4.71 ERA in 18 starts and a relief appearance -- making all of them with a partially torn ulnar collateral ligament in his pitching elbow. Because Lugo has had such trouble retiring hitters a third time through the batting order, it's possible the Mets look at him, too, as an answer in the bullpen. For now, he'll continue receiving chances to start.
Vargas, 35, went 18-11 with a 4.16 ERA last year for the Royals after missing most of the previous two seasons recovering from Tommy John surgery. Discounting those seasons, Vargas has averaged 188 innings per year since 2010.

The Mets had high hopes a year ago for Gsellman, which the right-hander's 5.19 ERA in 25 appearances promptly dashed. They had lesser hopes for Rafael Montero, who is now out of Minor League options. Those two, Chris Flexen and even prospect Corey Oswalt will compete for roles this spring, in what promises to be one of the most hotly contested positional battles around baseball.

"Everybody looks healthy," catcher Travis d'Arnaud said. "Everybody looks great. Not only do they look great, they all feel great from what I'm hearing, too."