TEMPE, Ariz. -- It's rare for a rookie to win over the hearts and minds of veterans as quickly as safety Tyrann Mathieu did with the Arizona Cardinals.
But the third-round pick impressed everyone with his work ethic and passion for the game. That's why many players were somber after finding out that Mathieu suffered tears in his left ACL and LCL last Sunday against the Rams.
Mathieu will undergo surgery within the next 10 days or so, and he's expected to miss at least a portion of training camp.
"He's been bawling since he's got the news," said cornerback Jerraud Powers. "It's going to be a huge blow. I just feel bad for him. Guys like him and (cornerback) Patrick (Peterson), football is the world and more to them. He (Mathieu) really feels blessed just to be on the field."
Mathieu will be difficult to replace. He has been the team's nickel cornerback since the start of the season and moved into the starting free safety job six weeks ago.
He participated in 88 percent of the defensive snaps this season and in 99 percent of the ones in the five games prior to last weekend.
"This will be a long one," coach Bruce Arians said of the rehabilitation process. "I won't attempt to say how long because it's individual guys now."
Arians has lobbied for Mathieu to be named defensive rookie of the year and said on Monday that the injury shouldn't change that.
"He meant a lot to us because of his flexibility," Arians said. "It will take two guys to take his place."
Rashad Johnson, who lost his starting safety job to Mathieu, will return to the lineup. In nickel situations, it's likely that starting cornerback Powers will move inside with Antoine Cason coming off the bench to play one of the outside spots.
That's what the Cardinals did after Mathieu went down in the third quarter.
"My thing is, it's more about his personality, his urge and his mentality on the field," outside linebacker John Abraham said. "Even though he's a young guy, he prepares like a vet and he acts like a vet. I think that's one of the biggest things we're going to lose."