TEMPE, Ariz. -- Arizona Cardinals safety Tyrann Mathieu's return to the field could come in front of a national audience.

During a radio interview with Adam Schein on SiriusXM Radio on Friday, Cardinals general manager Steve Keim said Mathieu could be healthy enough to play by Week 1 of the upcoming season, when Arizona hosts San Diego on "Monday Night Football."

"We think there's a chance that he'll be back by the beginning of the season," Keim said.

Mathieu tore the ACL and LCL in his left knee while returning a free kick in Week 14 in 2013 against the St. Louis Rams, and initial reports had him out at least nine months. Last month, Cardinals coach Bruce Arians said he anticipated Mathieu to start training camp on the physically unable to perform list.

Keim's comments on Friday reflect Mathieu's progress in his rehabilitation.

"He has been a gym rat," Keim said. "He's in here all the time. We have to kick him out of the building and tell him 'Tyrann, go home for a little bit.' He's always in the training room doing his rehab."

Recovering from an ACL tear has been expedited because of advances in technology over the past 10 years. But recovering from an LCL injury can be more complex while the stability of the knee is rebuilt. After Mathieu's surgery in December, Keim didn't want the young safety to get caught up in dates and timelines.

But Mathieu apparently hasn't had issues hitting and surpassing plateaus since his surgery in December. Keim cited Mathieu's "passion and his toughness" for helping the 22-year-old progress through his rehab.

"I told him, 'Ty, don't listen to anybody because nobody can tell you and pinpoint the exact return date. That's up to you,'" Keim said. "And he's a machine. He's the kind of guy that I really think can come back a lot earlier than people anticipated."