But for as much as he's itching to get back on the practice field, Mathieu, who tore his ACL and LCL in Week 13 last year, has a standard for his return.
"I don't want to go out there if I'm not the guy I was last year," he said Wednesday.
It's a high benchmark. Mathieu started 11 of 13 games his rookie season and blossomed as a slot corner and free safety. His nose for the ball while roaming the secondary led him to becoming a finalist for defensive rookie of the year. He proved he didn't lose a step after missing his junior season at LSU.
Now, he just has to prove he can make a football move again.
While his teammates practice inside, Mathieu spends his days rehabbing and practicing on a field outside University of Phoenix Stadium with assistant trainer Chad Cook. Eight months after his injury, Mathieu said he can do "pretty much anything." He's been working on increasing his reps and speed.
The aftermath of every practice is different. Some days he's sore, other days he feels great, and then there are the days Mathieu feels like he didn't give 100 percent.
"It's a mixture of feelings and emotions," he said. "So, I'm just trying to find that consistency and that's when I'll know I'm ready."
There's no hard timetable on his return. Arizona opens the preseason Saturday against Houston. Mathieu said Wednesday he expects to be back at practice in two to three weeks.
"I shared it with [Arians] but I don't think he takes me too seriously," Mathieu said with a smile.
An important part of his return, however, is honesty. As much as he wants to play, Mathieu knows he can't give the doctors and trainers false reports.
But if he's close, a little white lie won't come between Mathieu and the field.
"I have to be honest with them," Mathieu said. "I think if I'm 90 percent I'm going to say I'm 100 percent. I just want to play football."