There's always a guessing game each season to predict how well top players will return following major injuries the previous season.
Justin Houston, Pernell McPhee, Brandon Pettigrew, Corey Linsley, Dion Lewis, Breno Giacomini and Ladarius Green didn't recover fast enough to be active for the opener and are on the physically unable to perform list. Jamaal Charles wasn't healthy enough to play in the Chiefs' opener coming off last year's ACL surgery, but he could be on the field soon.
Here's how the stars coming back from major injuries performed in Week 1, and how they could perform for the rest of the season.
Week 1 stats: 7 tackles
Mathieu, who played all 71 defensive snaps against New England, still has his range and closing speed coming off ACL surgery. The surprising thing in the loss to the Patriots is that he wasn't involved in slot coverage much. He played deep safety most of the game. That could have been because the Cardinals were starting a rookie cornerback (Brandon Williams) opposite star Patrick Peterson. Regardless, Mathieu is a star, and he looked like his old self coming off the injury.