Kevin Kolb took snaps with the starters Wednesday. Reid again made it clear that Kolb will start against the Saints if McNabb can't play.
Jeff Garcia, picked up by the Eagles on Tuesday, would be Kolb's backup. He will be the No. 3 emergency quarterback if McNabb starts.
Michael Vick and Garcia will share snaps running the scout team this week. Vick is not eligible to play until next week against the Kansas City Chiefs.
McNabb cracked a single rib when he was crunched by several defenders on his 3-yard touchdown run in the third quarter of last week's win at Carolina. He didn't immediately get up after the touchdown, and was attended to by Eagles trainers before eventually leaving the field on his own.
Reid said McNabb's ribs need to get "sticky" - or, not move up and down - before he should play.
Kolb has never started an NFL game or thrown a touchdown pass.
"This is his opportunity to present to the rest of the league what he's all about," Garcia said. "Hopefully he takes advantage of all of that."