The offensive lineman, drafted by Chicago in the first round of the 2008 NFL Draft, has bounced around from left tackle to right tackle -- and over to left guard, where he started the final 11 games last season during the Bears' playoff push.
"That would be hard to say," Smith told the newspaper. "It's been pretty tough to say for Chris because we haven't been able to lock him in at one position. We made improvement through the course of (2010), when we were able to lock in five guys and keep them there. Chris has moved so much."
Smith acknowledged that finding a permanent place for Williams is a priority for the Bears this offseason.
The 6-foot-6, 315-pound Williams started 13 games last season and has 29 starts in 38 appearances over the past three seasons in Chicago.