The former Heisman Trophy finallist made his league debut during the Cardinals' pre-season win over the Green Bay Packers on Thursday, taking his first NFL sack.
The safety told the NFC West side's website: "The expectations can never amount to mine. I want to play a big role.
"Everybody always has something to say, whether it's good or bad. I just leave it at that and do what I do best, which is play football."
Head coach Bruce Arians added: "He was all over the field. That's the way he's been practicing every day."
The 21-year-old was selected by the Cardinals in the third round of this year's draft, despite spending the 2012 college season suspended for violating team rules.