TEMPE, Ariz. — It may be a while before we see Tyrann Mathieu on a football field again.

The safety left Sunday’s game with what was feared to be an ACL injury, and news came out Monday that things were even worse than originally thought.

Cardinals coach Bruce Arians announced Mathieu, who hurt himself returning a safety-kick in the third quarter of Sunday’s 30-10 win over the St. Louis Rams, will need surgery to repair the anterior cruciate ligament and lateral collateral ligament in his left knee. He added surgery is usually performed eight days after the initial injury.

“It’s a shame,” he said. “Prognosis is crazy — it’s individuals. Some guys…this will be a long one, but I won’t tempt to say how long because it’s individual guys now.”

Asked if Mathieu could be back in time for training camp, Arians was not optimistic.

“I would doubt that,” he said. “I would doubt that.”

The injury is a significant blow to a Cardinals defense that has evolved into one of the best in the NFL. Though a rookie, Mathieu had become one of the team’s most important players, as the safety had 68 tackles to go along with two interceptions and one forced fumble.

Able to play both safety and cornerback, his versatility in the defensive backfield will be missed.

“It will take two guys to take his place,” Arians said.

The coach said Rashad Johnson, Antoine Cason, Jerraud Powers, Bryan McCann, Javier Arenas can all help fill the void in coverage, but added with Mathieu, no substitutions were necessary.

With three games left in the regular season and the Cardinals still in the playoff race, replacing Mathieu on the field is certainly an important issue to figure out. However, much of the focus will turn to the 21-year-old’s future, especially given how bright it appears to be.

The road to recovery will be a long one. Of course, his path to this point has not exactly been a smooth one, so adversity is not anything new to the former LSU star. But his previous issues were of the self-made variety, and not injury related. That Mathieu has been able to overcome those, however, emerging as a key member of a playoff contender, bodes well for his comeback journey.

“He’s been fantastic, and he’s a leader,” Arians said. “Very seldom do you see young guys come in and become a leader like he has, especially in the secondary. But his personality is infectious with the guys because he loves football.

“He’ll stay out there and practice all day and go as hard as he can. Those are guys you miss.”

From here, it will be all about how Mathieu responds to something that happened to him.

“He was crying, he was sad,” Arians said. “He’s never been injured. These guys that get hurt for the first time, it’s devastating. And when you take away the thing he loves the most and works so hard for, he was devastated.

“But he’ll get over it, he’s strong. He’s got a lot of support.”

And that, along with everything Mathieu has shown him since being drafted in April, is why the coach is confident this will be little more than a speed bump for a rising star.

“He’s got a bright, bright future, just right now he’s got to work hard at getting his leg back,” Arians said. “And I’m sure he will.”

Follow @theAdamGreen