Center Dave Bolland's lingering back problems are becoming increasingly a cause for worry. Last season he played through the problem, but this season a sore back kept him out of much of training camp. He'll missed his second regular season game on Friday at Colorado, meaning the Hawks will play the first-place team in the Western Conference without their top two centers. Jonathan Toews practiced for the third straight day during the morning skate and could return to the lineup next week when the Hawks play four home games prior to their traditional two-week trip when a circus takes over the United Center.