Brady was drilled by defensive end Michael Bennett, forcing a fumble that was recovered by the Patriots. Brady also was sacked by Adam Hayward and took a big shot from Lavonte David on an incomplete pass.
Brady was partially to blame on the sack by Bennett, who had blown right by right tackle Marcus Cannon to get a clean shot on the unsuspecting quarterback, but the Patriots clearly have protection issues entering the regular season.
Vollmer dressed but didn't play Friday night, and he might not play before the regular-season opener against the Tennessee Titans. Mankins is coming off major reconstructive knee surgery and made his preseason debut Friday night.
"I survived," Mankins said of his debut, via Jeff Howe of the Boston Herald. "I didn't get anyone killed out there. That's always a good thing."
Mankins, whom Howe adds played around 10 plays, acknowledged the struggles of New England's offensive line.
"He (Brady) got hit back there a few times, and I think we had some negative runs, that's always disappointing," Mankins said. "We just know we've got to get a lot better out there."Follow Brian McIntyre on Twitter @brian_mcintyre.