Josh Koscheck doesn't need to fight anymore, but here he is in Bellator. The question is, why?

If there’s one thing Josh Koscheck would like to make clear, it’s that he doesn’t need to do this. In fact, it’s probably a bad idea. The man is 39, has been wrestling since he was 4, and these days his neck is so bad that he’s getting injuries in between his injuries.

That’s not an exaggeration, either. Koscheck (17-10 MMA, 0-0 BMMA) had surgery to fuse his fifth and sixth cervical vertebrae back in 2001, before he even started his career as a fighter. More recently he suffered bulging discs both above and below the site of the surgery, leaving him with painful nerve damage that left him almost incapable of using his left arm.

And yet here he is, nearly two years after his last fight in the UFC, preparing to step in the cage against Mauricio Alonso (12-7 MMA, 0-1 BMMA) at Bellator 172 on Friday night. But why?

It’s not for the money, which, again, Koscheck would like to emphasize that he does not need.

“I’m taking money out of my pocket when I’m fighting,” Koscheck, who fights on the Spike-televised main card at SAP Center in San Jose, Calif., told MMAjunkie. “When I’m here in training camp, I’m not focusing on my other businesses. And it’s not like the money’s going to make a big difference anyway. All my stuff’s paid for, and I don’t owe anybody anything. It’s not like I need to fight to pay my bills.”

So then why risk it? Why go through all the training, which Koscheck admitted he hates now more than ever, just to face a little-known Brazilian on the Spike undercard? It’s not like a win or a loss would do anything to alter the legacy he’s already built in the sport. And he can’t say for sure if there will even be a next time, considering his age and his injury history, so plotting a longterm run at the title seems farfetched.

If all the usual motivations don’t apply, why is he doing this? The short answer is, he’s been away from it just long enough to feel the force of its absence from his life.

“I think I had a great career, but you miss it,” Koscheck said. “When you’re away from it for a while, you miss the excitement of the crowd, you miss the competition. I compete every day in my businesses, but it’s different. When you’re out there putting it on the line in front of all those people, it’s a different taste. I missed it, so here I am.”

There’s also the issue of how things ended with the UFC. Koscheck ended a 10-year run with the UFC by losing five straight. For a guy who had never lost consecutive bouts at any point in his career prior to that dismal streak, this had to be hard to swallow.

Then there’s the personal enmity between Koscheck and UFC President Dana White. By the time he came to the last couple fights on his final UFC contract, Koscheck said, he was focused solely on fighting out the remainder of his deal and getting free of the UFC. His last two fights came within a month of each other as he rushed to finish out his contract, and what followed was a period of public animosity between Koscheck and White.

White told a FOX Sports radio show that things got so heated, Koscheck at one point physically threatened him, which Koscheck didn’t deny.

“Dana and I had some heated words,” Koscheck said. “I didn’t like the way he talked to me. I don’t disrespect him, but he’s got some big balls to talk to me the way he’s talked to me. So I told him I was going to get on a plane and go over there and beat his ass. We’ve had some good exchanges, and I’ve got some cute voicemails from him. But it is what it is. He’s obviously done well for himself, going from an aerobics instructor or whatever he was to a $300 million man. I can’t fault him for that.”

One reason he signed with Bellator, according to Koscheck, was for a chance to rematch Paul Daley, who sucker punched him following Koscheck’s decision victory in their 2010 bout. He went so far as getting the promise of a rematch written into his Bellator contract, he said, in part to prevent the UFC from exercising its matching clause, reasoning that the company wouldn’t be able to match an offer to give him a fight with a man it had banned.

But more than that, it seems difficult for the competitor in Koscheck, the thought of ending this way. He doesn’t want to go out on a five-fight losing streak and a feud with his former boss. What he wants, he said, is to “go out with a couple of wins.”

After all the years he’s put into this sport – he’s one of the few remaining castmembers of Season 1 of “The Ultimate Fighter” who’s still fighting – a part of him feels like he could walk away content any point, Koscheck said.

But then there’s that other part.

“It’s just something I have a passion for, and I missed going out there and getting my hand raised,” Koscheck said. “It’s been a while since I’ve had that happen.”

For more on Bellator 172, check out the MMA Rumors section of the site.