BOSTON » Does B.J. Penn really want to be a fighter?

Thirty-one years old is supposed to be the prime of an athlete’s career. On Saturday, Penn looked like he was 51 in his loss to Frankie Edgar at UFC 118 in front of a TD Garden crowd of 15, 575.

Leading up to the fight, Penn said he wanted Frankie Edgar to know the real B.J. Penn. He said the real B.J. Penn would be on display for all to see.

The worst part about it all is that he may have been right.

The former UFC lightweight and welterweight champion knows what it takes to be the best. A hard-core workout regimen with former trainer Marv Marinovich put Penn in the best shape of his life.

He showed how great he can be with dominant, one-sided wins over Kenny Florian and Diego Sanchez. He could do it all — strike with power, stave off takedowns at will and punish people with a ferocious ground game.

Against Edgar, it was the opposite. Edgar was the one who looked like a black belt world champion in jiu-jitsu. Edgar was the one picking up Penn and slamming him hard on the ground.

Longtime boxing trainer Freddie Roach once said Penn has the best boxing in MMA. Are we sure he didn’t mean Edgar?

There shouldn’t be any greater motivation than getting a second chance to face the guy who beat you the first time.

From the moment Penn was shown walking to the ring, you could almost see it in his eyes. Against Sanchez and Florian, he looked like a rabid dog, ready to unleash all of his skill on his opponent.

On Saturday, he looked tentative just walking to the ring. Mentally, he was so out of it he walked to the wrong corner and waited a good 10 seconds before finally figuring out his cornermen were on the other side.

Mixed martial arts is a sport evolving on a daily basis. As more and more people get into it, new and fresher ideas are coming about, making it much harder to stay on top.

For the second time in less than two years, and first at 155 pounds, we saw Penn manhandled to the point that it was almost tough to watch. Mouth open, gasping for air, eating combinations, getting taken down with ease, it was a bad night all the way around for the Penn camp.

It’s up to him where he goes from here. He knows what it takes to fully prepare for a fight, and for his last two against Edgar, he hasn’t been willing to do it.

He’s spent all of his time in Hilo, working with the same group of guys that surround him every day.

If Penn is going to continue on from here, he has to first figure out if he wants it. If what it takes is to get back with Marinovich or find another team that will push him and make him better in ways he’s not getting now in Hilo, is he willing to do it?

At 31, he has plenty of time to figure it out. Does he want to?

He said he wanted to fight every month if possible, but now more than ever, it’s most important he takes his time to step back and figure things out.

If he wants to put the proper time and effort into it, then it’s back to the grind. But if he doesn’t, then it might be time to think about hanging up the gloves.

The worst thing he can do is continue to think he can go out there unprepared and unmotivated like he was against Edgar. If that’s the case, then a repeat of Saturday night is what awaits a man that nobody is used to seeing get beat up the way he did.

And nobody wants to see that.