Rookie tackle Chris Williams signs autographs.It’s still early in training camp — the second day, after all — but already there is cause for concern on the injury front. In addition to injuries to Olin Kreutz, Dusty Dvoracek, and Kevin Jones, rookie offensive tackle Chris Williams left Thursday’s practice with a back injury.

The severity of the injury currently is unknown, but it is awfully disconcerting that the Bears’ first round draft choice — who will be playing one of the most important positions on the field — already is suffering his first injury.

Hopefully, the injury isn’t serious and he’ll be back on the field shortly.