Kelly said that he has seen Wolff get better in his recent appearances and that there is a lot more to come from the rookie.
"[He] came in here as a rookie and is starting to play a little bit more as he got through the Chargers game, the Redskins game, and then the Chiefs game," Kelly told ESPN.
"There's an improvement as we've gone along. There's still a lot of work to be done, but we're happy with what direction he's heading in."
Wolff was the 136th overall pick in this year's Draft.