Coach Sean McDermott has already ruled out Allen (elbow) for this week's game against the Bears, Chris Brown of the Bills' official site reports.
Given the team's 2-6 record and the awful play of Derek Anderson and Nathan Peterman subbing in, this would have been the perfect no-pressure game to insert the rookie back into the lineup, but his long-term health will take priority here. Allen's next chance to play will come in Week 10 against the Jets, while it's worth noting if the team really wants to play it safe, the Bills have their bye in Week 11.