Colts quarterback Peyton Manning planned to undergo scans Wednesday in Indianapolis to see whether the fusion of his neck vertebrae is complete, and doctors then will determine the next step in his rehabilitation.

Manning has been unable to run or throw since Sept. 8, when he had his third neck surgery in 19 months, a vertebrae fusion procedure that removed soft tissue and attached the bones together with a graft. Wednesday's scans should show whether the graft has taken hold enough to increase his physical therapy.

Manning has been limited to the elliptical machine for cardiovascular work and some light, high-repetition weightlifting to restore strength to his pectoral muscles and biceps and triceps. Until his spine has fully fused and healed, the nerves can't regenerate, and without proper muscle strength, Manning would risk damage to his rotator cuff or elbow by throwing too soon.

Once Manning's doctors and the Colts' medical staff have reviewed the results of Wednesday's tests, Manning should know whether he can resume throwing and possibly return to the field this season.

After Indianapolis fell to 0-11 Sunday with a 27-19 loss to Carolina, Manning told reporters in the Colts' locker room that he would "probably check in with y'all this week."

The Colts and Manning have held out hope that he might be able to play this season, with a goal of being able to practice in the last two weeks of the season.

Chris Mortensen is ESPN's senior NFL analyst.