Vollmer suffered an injury early in the second quarter this past Sunday against the Miami Dolphins. In a shocking moment, Vollmer's screams could be heard over the telecast. Vollmer has been one of the best tackles in the league this year, so his loss is a huge detriment to the Patriots goals.
Vollmer has suffered from injuries throughout his career, which has led to his contract to be heavily incentive based. The Patriots owe Vollmer bonuses based upon the % of snaps Vollmer is able to play, with 2013 linked to a 90% figure, which Vollmer is now unlikely to meet.
In order to replace Vollmer, the Patriots will likely move forward with Marcus Cannon, who played well for the remainder of the game after Vollmer was removed. The Patriots also have Will Svitek to provide depth, but if a roster move takes place, look for the Patriots to bolster their thinning offensive line.
The normal recovery time for a broken leg varies based upon the severity, but it could range from 4-6 weeks for a "minor" injury, to Vollmer being out for the season. Based upon Vollmer's reaction on the field, I would (in my unprofessional opinion), lean towards the latter.