As the 4-6 Buffalo Bills prepare to fight to keep their playoff chances alive this coming Sunday against the Indianapolis Colts, they're likely to be reinforced by the return of two veterans to the lineup: running back Fred Jackson and defensive end Chris Kelsay.

Jackson missed last Thursday's win over the Miami Dolphins with a concussion sustained the week prior against New England. He is expected to complete concussion protocol today, and should be on the practice field when the team re-convenes Wednesday to begin installing the game plan for Indianapolis. When he makes his return to the lineup, it'll return C.J. Spiller - who registered a career-high 25 touches in the win over Miami - back to a timeshare role.

Kelsay, meanwhile, has missed two consecutive games after suffering a torn neck ligament during a practice leading up to the New England game. He participated in individual drills during Monday's practice, and is expected to practice all week. That doesn't guarantee that he'll play on Sunday, particularly if his injured neck doesn't handle practices well - and even if he does play, it's still expected that he'll surrender more reps to the likes of Kyle Moore and Shawne Merriman than he did before getting injured.

The news is not as promising for two more starters that have been out for a while: neither defensive end Mark Anderson nor cornerback Aaron Williams appear ready to return to the practice field dealing with their respective knee injuries. That means that the Bills will continue to platoon Moore, Kelsay and Merriman at end opposite Mario Williams, and the surging Leodis McKelvin will make his third straight start at cornerback opposite rookie Stephon Gilmore.