I'd like to see LaFell as that 'larger' slot WR matched up vs the smaller DB's personally. I think he and Olsen could really work the shallow/intermeiate routes while Murphy and Smith keep the safeties occupied high and outside.
That's what I was thinking. Lafell is good at catching in traffic, and having him running crossing routes up the middle is where I think he would shine. Probably wouldn't get the biggest stats for his career in this role (since he doesn't have much acceleration after the catch), but I think he'd be the most effective. When Smitty is ready to hang up the cleats, Gettis might be even able to slide into his role opposite Murphy (or vice versa, whoever doesn't get the role this year).