DENVER — Boxer Mike Alvarado was arrested on weapons charges three weeks before the biggest bout of his career.

His longtime manager, Henry Delgado, was "dumbfounded" to learn of the former world junior welterweight champion's latest run-in with the law as Denver police found a handgun in the glove compartment of Alvarado's Hummer over the weekend.

Sometimes, Delgado can't help but wonder this: How good Alvarado could be if he avoided trouble outside the ring as well as he does inside the ropes.

"I've never seen him put 100 percent into his career," Delgado told The Associated Press in a phone interview Monday. "It's what you do in between the fights that defines you. It's how you're living, how you're taking care of yourself.

"Nobody has seen what he could've been. He wouldn't have any losses if he was committed 100 percent."

Alvarado (34-3, 23 knockouts) is still scheduled to step into the ring against Brandon Rios for a third time on Jan. 24 in Broomfield, Colorado. The winner will receive a chance at an even more lucrative payday.

For the loser, it just might mean the end of a career.

That's why Delgado has pleaded with the 34-year-old Alvarado to take this fight seriously as he trains out of Delgado's gym near Coors Field.

"I've talked to him until I'm blue in the face," Delgado said. "You think everything is going great and this happens."

Alvarado, who grew up in Denver, was a passenger in his Hummer when officers stopped it early Saturday because it had expired license plates, according to police reports. Officers said they saw Alvarado appear to be pushing something into the glove compartment and trying to close it.

He told police the Hummer was his, and that he knew the plates were expired because he had just gotten it out of the shop, the reports say. Police arrested him on other outstanding warrants and then found the gun while searching his vehicle.

In 2008, Alvarado pleaded guilty to aggravated driving with a revoked license, a felony. As a convicted felon, Alvarado cannot legally possess a firearm.

Court records show he was wanted on an outstanding warrant in neighboring Adams County for the same offense, possession of a weapon by a previous offender. Authorities were also seeking him on an outstanding traffic offense.

Court records also show he was released from the Denver jail on bond, but they do not list an attorney for him.

Alvarado — who goes by the nickname "Mile High" — has dropped his last two bouts, including one against Ruslan Provodnikov in October 2013 in front of a hometown crowd, losing the World Boxing Organization junior welterweight title in the process.

Then he lost a 12-round unanimous decision to Juan Manuel Marquez.

Now, Alvarado is trying to get his career back on track against Rios. The friends have split their previous two action-packed bouts, which featured 3,003 punches thrown over 19 rounds.

Carl Moretti, vice president of boxing operations for Top Rank, which is promoting the fight, said "the show is still going on" despite Alvarado's arrest.

"Obviously we don't condone what happened," Moretti said. "Unfortunately, this is the drama you sometimes get with a Mike Alvarado fight."

The officer who arrested Alvarado on Saturday wrote in the report that he knew Alvarado from past run-ins. Alvarado was jailed last year on an outstanding warrant for failing to make a court appearance in a traffic case. Last month, he told the AP he was also detained in Las Vegas for "procrastinating on a driving ticket."

He said he did 1,000 push-ups a day in his cell because he couldn't train.

Since then, Alvarado added that he has "just been staying focused on my training. Doing what I need to do to win this fight."

Alvarado beat Mauricio Herrera on April 14, 2012, which remains one of his top performances.

"That night, that was Mike Alvarado," Delgado said.

Asked if he expected Alvarado to be ready by fight night, Delgado said, "Hopefully. If this doesn't mess him up. I'm very concerned."