It's mostly Kyler throwing short of the sticks. Kyler's average yards per attempt on 3rd and 7+ was 5.18. OOF. Three first downs in 43 passing attempts (this is also pretty small sample sizes here, but high-leverage situations).
For the whole Cards offense, there were 70 plays of 3rd and long, rushed 30/passed 43/7 sacks.
Seven passing first downs, four rushing first downs.
Worth noting that those rushes on 3rd and 7+ are mostly going to be "3rd and no chance" and it's just getting more yards for the punt, or closer to a FG.