Who will return punts for Cardinals?

The Arizona Cardinals lost Tyrann Mathieu last season when he blew out his knee while returning a punt. Fellow Cardinals cornerback Patrick Peterson was a punt-return beast as a rookie in 2011, scoring four touchdowns. However, his success has dwindled the past two seasons. He hasn't scored since '11, and his YPR has dropped from 15.9 yards in '11 to 8.35 in '12 to 6.0 last season.