Matt Harvey pitches during the second inning of a spring...

Matt Harvey pitches during the second inning of a spring training game against the Detroit Tigers at Tradition Field on March 6, 2015, in Port St. Lucie, Fla. Credit: Michael Ross

JUPITER, Fla. — Matt Harvey’s blazing fastball once shaped his persona as the city’s real-life Dark Knight, making the Mets righthander one of the most electrifying pitchers in baseball.

But Wednesday, a more vulnerable, weathered and diminished version of that once-dominant ace acknowledged that he may be in for a slog. Harvey’s velocity hovered in the 92- mph range — just as it has in all three of his spring starts — as he got roughed up in a 6-2 loss to the Marlins.

After just his third outing since having a rib removed to remedy thoracic outlet syndrome, Harvey provided a sobering reminder of the uncertainty that surrounds his right arm. He insisted he’s comfortable pitching in the low 90s, rather than the high 90s that had always been within his reach, while admitting it could be a while.

“It’s going to be there or it’s not, and I have to go out and pitch,” Harvey said. “And I think after today I feel really confident going into my next outing and moving forward.”

Terry Collins took a more reserved approach, saying he wasn’t worried about the lack of velocity on Harvey’s fastball, and that he’d reserve judgment until the end of spring training. But pitching coach Dan Warthen said it could be months until the heat on the fastball returns.

“End of May,” Warthen said when asked how long it could be until Harvey’s arm strength returned.

Until then, Harvey must encounter the same challenge that Jacob deGrom faced early last season, when he was forced to make do without his fastball.

New York Mets pitcher Matt Harvey during a spring training...

New York Mets pitcher Matt Harvey during a spring training workout in Port St. Lucie, Florida, on Feb. 13, 2017. Credit: Newsday / Alejandra Villa

“He’ll probably have to pitch there for a while,” Warthen said. “Most history says that somewhere around 10 months out (of surgery) is when you get your full strength back. He’s certainly capable of pitching with the velocity he has and his ability to locate.”

Harvey, who turns 28 this month, never has worked in the big leagues without the added leeway of an elite fastball. Even last season, when he dealt with numbness in his fingertips as a result of thoracic outlet syndrome, Harvey’s average fastball was 95 mph.

But Wednesday, Harvey topped out at just 94, and when he tried to muscle up on his pitches, he dealt with the opposite effect. Warthen said those offerings came out closer to 90 mph. It’s those mistakes that the Marlins punished.

Harvey allowed four runs (two earned) and five hits in 3 1⁄3 innings. He threw 68 pitches. While his fastball was again lacking, Harvey took encouragement from the smoothness of his mechanics and the touch on his secondary offerings.

Harvey was even able to laugh off taking an Adeiny Hechavarria liner off his leg, then getting charged with two errors when he fumbled as he scrambled to retrieve the ball and fired a wayward throw to first base.

“I think it’s still early,” Harvey said. “I think spring training is what it is. Today, I’m not worried about the results. I’m happy with the way I felt mechanically. I threw a lot of good pitches and I threw some bad ones. I think that’s excitement for my next outing. The velocity, all of that will come in time. I’ve just got to keep pushing forward.”

With little more than two weeks to Opening Day, Harvey’s focus appears centered on adjusting to the new normal, the latest challenge in an at-times brilliant, often turbulent and relatively short big-league career.

“We’ve had it and he has to realize that he’s a pitcher, he’s not a thrower,” Warthen said. “He doesn’t need that high-end velocity. He can use his other pitches and still get a fastball by you.”

Harvey had surgery last July. Even while he’s been knocking off rust throughout spring training, rival talent evaluators have seen no signs that the velocity dip could be permanent. But they have come away with the impression that it could take some time, a complicated reality for pitchers coming off surgery for TOS, a condition that has ended careers.

“It’s kind of a new surgery for me,” Harvey said. “Obviously, with Tommy John, you know so many guys have come back and done this. But I’m not looking to throw 100 mph again, or 97 even. My job is to get people out no matter what I’m throwing. And I’m looking forward to it.”