Yeah I really doubt that Cena was just too lazy to put on the sling and sell. I know it's cliche to say, but creative probably had something to do with it--I'm willing to guess they wrote up the segment with Cena being fine since they want Cena to go into OTL 100% and NOT in a sling. At Extreme Rules and the week after, the plan probably WAS for Cena to take some time off and/or sell the injury. As we all know, The past few Raws have been changed so many times, at some point the Cena/Ace match was decided and you really can't have Cena go into it one-armed.