I'm convinced that Free was having a real difficult time switching from Hudson Houck's blocking schemes to Bill Challahan's early in the season. His play was just too bad early and he improved too much late for that not to be a big part of it, IMO. He just looked lost in all the early games but looked like another player the last few games. He was ok in 2011 and ok late 2012... but for a few games at the start of last year he was simply horrid.
I know he was overpaid, but if he takes a significant pay-cut, I'd certainly let him try to compete in Callahan's system year two. If he takes the cut, at least watch him through training camp to see if maybe the switch to Callahan and the switch from left to right messed him up for a while.
If he's willing to take the big cut to free up significant salary cap money, then it is worth it to bring him back, let him compete, and not take a big hit with dead money.
If he sucks in camp again... cut his ***.