Wheaton has been a fairly average kick-returner. Brown has shown that he can take it to the house on any given punt, and since it's the playoffs, why not use him on kick returns too? Touchbacks at Heinz field are harder to come by for the opposing team; whoever is back there this Saturday should get his chances.
I understand that using Brown during the regular season was too risky in terms of injury, but now that it's the playoffs shouldn't the coaching staff bust out all the stops?