Peyton Manning

It's a big day for Peyton Manning.

Earlier this week, Denver Broncos coach Gary Kubiak said Manning would have a "big workout" on Saturday to evaluate the quarterback's progress in his rehab from a partially torn plantar fascia in his left foot.

Manning has already been ruled out for Week 16. Brock Osweiler will make his sixth start of the season Monday night versus the Cincinnati Bengals.

NFL Media Insider Ian Rapoport reported Friday on NFL Network that the Broncos are trying to gain understanding on two key questions: Will Peyton Manning be able to practice next week and will Peyton Manning ever be physically able to play for the Broncos again, the story said. Manning returned to practice on a limited basis last week, but suffered a setback and had to sit out last Friday. This week, prior to Saturday, the quarterback has only been able to rehab and throw on the side. Saturday marks a pivotal for Manning's future in Denver and possibly his NFL career. If it goes poorly, we could have seen the last of Manning in a Broncos jersey, the story speculates.