The Patriots still don't know who will be lining up at center or right guard this season, but they have a right tackle now.

Sidelined throughout camp following offseason back surgery, Sebastian Vollmer made his first appearance of the preseason and played roughly 10 snaps during Wednesday's loss to the Giants. He was pulled midway through New England's third offensive series and he told reporters later that he felt fine.

"I'm excited to be out there," Vollmer said. "I think that it was real good."

Left guard Logan Mankins (knee) was on a similar program in his first game back Friday night against Tampa Bay but didn't play against the Giants. It's still not known if either player will be ready in time for the Sept. 9 opener in Tennessee.

"We'll see," Vollmer said. "I'll prepare myself to play the whole time, and we'll take it day by day."

Marcus Cannon, who has drawn criticism for his spotty play this preseason, would likely start at right tackle if Vollmer isn't ready in time. Mankins' replacement at guard would depend on who wins the battle at center among four candidates: Dan Connolly, Dan Koppen, Ryan Wendell and Donald Thomas.

The line could be further solidified if right guard Brian Waters, who still has a locker at Gillette Stadium, decides to report during the next week.

Demps OK after scare: Rookie running back Jeff Demps suffered a leg injury during a fourth-quarter punt return and received attention from the training staff on the sidelines. He was given an MRI after the game that revealed no damage, and he said he was feeling fine.

Nick Underhill covers the Patriots for Follow him on Twitter @CBSSportsNFLNE or @nick_underhill.