McCown made eight appearances and five starts for the Bears in 2013, finishing with 13 touchdowns, only one interception and a passer rating of 109.0. It's not easy to figure out how that metamorphosis occurred. McCown is the first to admit it.
"I don't know why it came together at this point," McCown told the Chicago Tribune. "Maybe it just took me 12 years to figure it all out. Or maybe I needed Coach (Marc) Trestman and Coach Cav (quarterbacks coach Matt Cavanaugh) and Jay (Cutler) and all these receivers. I don't know. I can't explain all that. All I know is what happened."
Now McCown, 34, must decide where this unexpected success takes him next.
"It's hard to want to be anywhere else," he said of the Bears. "But the balance of that, too, is our reality. This is probably going to be the last time I stand in free agency with this kind of leverage. So there's an understanding of an opportunity here to gain some more resources both to take care of our family and to do more good with."
"I have to be willing to go somewhere else, if that's how it breaks."
The more likely scenario has McCown signing a one- or two-year deal elsewhere and getting the opportunity to be a starter. Whether he can continue his late-career surge without the guiding hand of Trestman remains to be seen.