Trainer Mike Stafford believes Floyd Mayweather Jr. should move quickly if he wants to fight again.

The clock is ticking on Floyd Mayweather Jr.’s comeback. The older he gets, the less likely he is to return. If that logic holds true, then the odds of Mayweather coming back just got longer on Wednesday, when Mayweather celebrated his 39^th birthday.

So what happens now? The biggest unknown in the sport is whether he will honor his retirement. Only Mayweather knows. He still seems capable of boxing at the highest level, judging by his easy win over Andre Berto in September. Should he try to come back later this year? Or next year? Or the year after? What’s the expiration date on greatness?

Mike Stafford, who trains junior welterweight titleholder Adrien Broner, laughed at the question. Stafford believes Mayweather could still dominate his rivals. But time is running out.

“If he comes back now, it’s not like he really lost any time,” Stafford told RingTV.com. “It’s just his usual rest (when he fights in September and May). I think the time frame for him to fight again, it really hasn’t gone. But if he were to wait a couple years from now, it wouldn’t be the same thing. I wouldn’t wait until I’m 41 because things can happen. If he does it now, it’s not really like a retirement. But if he waits, then it shouldn’t be against no top contender. If I was him, I would do it now.”

Sherif Younan, who trained former titleholder Paulie Malignaggi for his last fight and also guides his son, 7-0 light heavyweight Sherif Younan Jr., echoed Stafford’s views: If Mayweather decides to come back, he needs to seize the moment because Father Time catches up to everyone.

“If he fights now, I would say it’s OK,” he said. “But it would be tough a year or two from now. But this year I believe he would still look good. We know how he prepares and always comes in top condition. But a year or two from now, when you’re not being active and you try to come back against a young fighter like a (Keith) Thurman or a (Danny) Garcia, it would be a challenge because age always catches up to you at some point.”

While professing not to have any inside information, Stafford wouldn’t be surprised if Mayweather returned for one more fight.

“If the money is right, he’s going to do it,” he said. “That’s Floyd. He just took off before and came back. These athletes are athletes. They miss the game so much, so you just never know with them. I think in the background people are offering him stuff. He’s an athlete and the champion in him is going to want to come back.”