With Sam Bradford sidelined and undergoing the NFL's concussion protocal, Mark Sanchez is the unofficial starter for Week 11's game against the Buccaneers.

Which means Thad Lewis will likely be his backup.

Meaning, if anything happens to Sanchez Sunday afternoon in South Philly, a quarterback with six career starts in six professional seasons will take over Chip Kelly's offense.

"Sometimes it's the next man up," Lewis said after practice Tuesday. I haven't been told anything, but you go out there and take reps. You have to think 'what if someone got sick the night before the game?' You have to practice like you're going to go."

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Lewis started one game in 2012 with the Browns, and five in Buffalo a season later. He has five NFL touchdowns to four interceptions and was picked up in Week 2 by the Birds.

"I've had my nose in the playbook since I've gotten here, and it's become pretty much second nature," the undrafted free agent from Duke said. "I feel very comfortable."

Bradford is not expected to be out long term, and the Eagles are not likely to sign another quarterback. So don't be surprised to see No. 9 prowling the sidelines during the next couple weeks.