In retrospect, Trevor May made a critical mistake a couple of years ago, one his career hasn’t recovered from yet:

He pitched too well.

“We were in a pennant race, and I was excited to do whatever we needed to try to win it,” May said of his midseason switch to the Twins bullpen in 2015. “I still feel that way. But it might not have been the best thing for me in the big picture.”

That’s because, as brilliant as the righthander pitched in relief that year — a 3.15 ERA in 34 mostly high-pressure innings, plus 39 strikeouts and only eight walks — May now suspects that changing roles might have been detrimental to his health. Not to mention his career.

May approaches spring training, his fifth big-league camp, with roughly the same uncertainty as a year ago. Healthy again after an injury-filled 2016, the 27-year-old has been promised a shot at a starting role, just as he was last year. This time, though, he believes the opportunity is legitimate.

“Last year, the [pitching] schedule was set early in the spring, and there were four guys who were [scheduled] all through the spring, and then guys like me who were more start-to-start. So it was pretty clear,” May said, that manager Paul Molitor and General Manager Terry Ryan preferred to keep him in a setup role. “I’m not stupid. I knew there were eight starters [in competition for five jobs] and I had bullpen experience. I knew that the easiest decision would be to put me in the bullpen.”

May pitched three times in Fort Myers, including one start, before being informed with three weeks left in camp that he would indeed remain a relief pitcher. “Tempting — that’s the word,” pitching coach Neil Allen said. “He pitched so well in a setup role, it was tempting to just keep him out there and see what he could make of it.”

May accepted the news and was determined to repeat his success, he said. But his body wouldn’t cooperate.

A month into the 2016 season, May’s lower back began to ache. He went on the disabled list because of a back strain, returned briefly, then suffered back spasms that kept him out for much of May. By August, the pain was worse; May pitched only once after Aug. 6, and was eventually diagnosed with a fractured vertebrae, ending his season with a 5.27 ERA over 42⅔ innings.

Four months of rehabilitation have paid off, however, and May says he is pain-free and throwing almost daily. “I feel normal again, to where I can stand up straight, where I don’t cock my back to one side when I sit in a chair, those kind of weird things I didn’t even realize I was doing,” May said. “It’s exciting to not feel stiff and sore all the time.”

May is excited about trying to use his four-pitch repertoire, including a mid-90s fastball, as a starter again, too. “Pitching with a set routine, with four days off between starts, that’s going to make it easier to stay healthy,” he said. “When you don’t know when you’ll pitch, it’s a lot harder to get into a routine that will protect your back.”

He is running regularly and throwing longer bullpens, mostly because of a conversation he had with new Twins Chief Baseball Officer Derek Falvey, who assured May the team pictures him as an every-fifth-day pitcher.

“[Falvey] seems really sincere about it. He said they want to get the best out of players, and I believe I can help us immensely by throwing 200 innings,” May said. “I’m not saying I have to have an amazing spring, by any means, but I have to show I’m ready to go. I have a starter’s mind-set that I can throw all my pitches right away. … If the health is there, I feel like I can slide in there.”

Actually, May might never have slid out of there, except for circumstances out of his control. May was enjoying a promising second season in 2015, and delivered a stretch of five quality starts in a seven-start stretch from mid-May to late June, striking out 41 hitters with only seven walks. He seemed to be establishing himself as a fixture in the rotation.

“People forget, the only reason he got bumped out of the rotation two years ago was that Ervin [Santana] came back from [an 80-game steroids] suspension,” assistant GM Rob Antony said. “We looked at it and said, ‘Which guy is best able to adjust to the bullpen?’ And it worked out exactly like we hoped — he thrived in that role, and we were in the race.

“If not for that, he probably finishes the season in the rotation, stays in it last year, and we never have this decision.”