I tend to forget that things are done differently under a new regime. Sometimes you'll get players who were overvalued by one coaching staff and end up being knocked down several pegs. Sometimes the new staff will do that regardless of how well the guy plays.
That seems to be what's happening to Demorrio Williams, courtesy of Steve Wyche of the AJC. D-Mo was a bit rusty in his first regular season game, and Petrino didn't hesitate to yank him in favor of Stephen Nicholas. Going back over the game I didn't notice any particular moments where D-Mo looked so awful that he should have been yanked, but clearly the coaching staff saw something. Now it looks like the two linebackers will be splitting time in the next game, and it might go a little deeper than that.
Nicholas is the more prototypical linebacker to begin with. He's not nearly as fast as D-Mo, but he will probably learn to tackle more cleanly and cover his gaps better in the long run. D-Mo really thrives on coming around the edge and pursuing, even though he overpursues at times. Nicholas is probably the kind of guy Petrino wants out there opposite Michael Boley, though, so it's really only a matter of time before he takes over the job. Even though he looked pretty impressive for a rookie, I don't see any rush to get Nicholas the starting job. Rust or no rust, D-Mo is the more dynamic player and has a proven track record of piling up tackles. With this year's margin for error being very small, the Falcons should be rolling out with the team that gives them the best chance to win. There'll be plenty of time later this season to get a look at the rookies, probably, so let's not rush into this when we've still got a very real shot at doing well.