Cub Swanson may become a free agent after his UFC fight with Brian Ortega in December.

It appears Cub Swanson may enter 2018 a free agent.

Swanson (25-7) is scheduled to face Brian Ortega in the main event of UFC Fight Night on Dec. 9 in Fresno, California. As of now, that event marks the end of his UFC contract.

The perennially ranked featherweight has been fighting for 13 years and has never appeared in a championship fight. He says he hasn't made enough money to comfortably retire.

At this point in his life, Swanson, 33, feels he's earned a contract that would guarantee both. The UFC has announced a featherweight title fight between Max Holloway and Frankie Edgar on Dec. 2, and Swanson wants it in writing that he's next. He also wants his next deal to pay him the kind of money that would secure his family's future.

After months of negotiations, Swanson didn't feel the UFC's offers did that. So, barring reopened talks, he intends to fight out the deal.

"It's a power move," Swanson told ESPN's Five Rounds. "Of course I want to get paid more. The thing people don't understand is that I've got to a point where I'm making good money and it's enough to live on, but it's not retirement money. Not even close.

"I've been doing this for 13 years and I'm in the prime of my career, but at some point it's going to dip off, and I'd like to walk away before I start having really bad performances -- with enough money in my account to make smart investments and do the right things. I just want that opportunity."

Swanson's frustration at never receiving a title shot is reasonable. He's suffered several key losses, but between his WEC and UFC careers, he holds an overall record of 15-6.

And all six opponents he lost to have either won or challenged for a UFC title.

"This is the 20th title fight since I've been in this division," Swanson said. "I've been in the top tier of guys my entire career. It's a little frustrating seeing somebody like Frankie, who is great, get tons of title fights. I just don't understand it.

"I wanted some leverage for that [in my contract]. I'm next. They're always saying, 'We can't guarantee anything,' and it's like, 'Come on. Yes, you can.'"

Brian Ortega has won all 12 of his fights as a professional and faces Cub Swanson in December. Al Powers for ESPN

Swanson believes that not signing a new deal has already affected his relationship with the UFC.

His December fight against Ortega (12-0) was leaked in the public before the UFC offered it to him. And he believes the UFC didn't book a fight against former champ Jose Aldo because he's not locked into a long-term deal.

"My honest opinion is I feel I may have upset somebody because I didn't take a new deal," Swanson said. "That's just how it works. I'm very happy with the UFC, but I would like to position myself better. I think I probably would have gotten Aldo or [Ricardo] Lamas if I'd signed a new contract with them. I didn't, and now I'm getting a young, hungry up-and-comer."

Fighting out of Jackson-Wink MMA in Albuquerque, New Mexico, Swanson says his focus is solely on Ortega, following the failed talks on a contract extension.

He says he ultimately wants to remain in the UFC, where he's fought since 2011, but he remains committed to his contractual demands.

"My last couple fights, I feel they're showing that they see me more as a gatekeeper, having all these young up-and-comers fight me," Swanson said. "I've got no problem knocking them off. To say I'm getting paid the same to fight Aldo or Frankie, as Brian Ortega? I'm like, 'OK, I'll take this youngster, who hasn't been in the five-round wars yet.'

"Unfortunately for Ortega, I'm pretty pissed off for this situation and I'm going to take it out on him."