PORT ST. LUCIE, Fla. – Five hundred ninety days. Matt Harvey ponders the time he's spent in the trainer's room, grinding through shoulder-strengthening exercises, stomaching all the other nonsense that comes with recovering from Tommy John surgery, and it comes back to that: When he steps on the mound at Nationals Park on opening day April 6, it will have been 590 days between major league pitches.

This seems like a lot because it is. And that's not necessarily a bad thing. Doctors and trainers almost all agree that to get a true sense of a pitcher's recovery from an ulnar collateral ligament transplant takes 18 months. The tendon used to tie together a pitcher's elbow doesn't transform into a ligament until about that time. To rest the arm throughout the process is a blessing most don't get.

Whatever disappointment Harvey had in not returning last season has vanished. Eventually he recognized that he's one of the lucky few – the pitcher who gives his arm even more time to heal than the standard 12-month timetable – and that while no data exists to prove longer recoveries equal better results, enough experts agree on it to give him comfort.

View photos Matt Harvey was 9-5 with a 2.27 ERA in 2013 before his season ended. (AP) More

"I was looking at a 17-month recovery, even if I didn't want it. And it was the best decision," Harvey said. "Going into a fresh season at 17, 18 months, I couldn't feel any better about it."

Neither could the Mets. The squabbles with Harvey over him wanting to return last season faded into an understanding that coming back at 11 months would do no good for either party, particularly in a lost season. His return now has enlivened the Mets, whose playoff aspirations are no longer apparitions. Manager Terry Collins called a recent curveball thrown by Harvey "stinking dynamite." Teammates will gather to watch him throw live batting practice Friday. All of it barrels toward the Mets' spring training opener and finally their season opener, both expected to go to Harvey.

It's easy to forget how good he was in 2013 when his season ended so abruptly. Harvey regularly touched 100 mph with his fastball, and his slider, curveball and changeup were above-average pitches, too. Only a handful of pitchers – Felix Hernandez and Clayton Kershaw among them – boast four such offerings. It's a heady comparison for a pitcher who will turn 26 years old before the season starts and have pitched the equivalent of one full season.

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Still, the Mets handled Harvey with the sort of caution being taken more and more across the game. Arizona wants to give Patrick Corbin almost 15 months before he returns. Jose Fernandez's targeted return date of June or July might be optimistic considering where he stands in his current progress. The rash of two-time Tommy John cases last season scared teams into slowing down the process, particularly with their most valued assets.

There isn't much precedent for long recovery times. Often the timing matters most, and Harvey's was perfect for the extra rest. He injured himself in late August 2013 and tried to rehabilitate the injury. It failed, as almost all partial-tear rehabs do, and he underwent surgery Oct. 22, 2013.

Four months later, he started throwing, as do most pitchers rehabbing from the surgery. And at 11 months, as the Mets' season wound to an end, he almost certainly could have thrown in the big leagues. Rushing him back wasn't going to help his 2015 season, though, and the perceived value of extra rest dawned on Harvey eventually.

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