Bills roster bubble to take shape during Bills vs. Colts

Tomorrow afternoon at 1:30PM ET on NFL Network, the Buffalo Bills will open their 2013 preseason schedule with a road trip to take on the Indianapolis Colts. It will be the first time that players competing for a spot on the Bills' 53-man roster will have an opportunity to separate themselves from their teammates outside of the practice setting.

In particular, we'll have our eyes on the following positional groups and players when the Bills and Colts kick off tomorrow.

Running Back

We know what the top of the Bills' running back depth chart will look like, but two questions remain here: will the team keep three or four runners, and who among Tashard Choice, Zach Brown and Kendall Gaskins will step up to claim that spot (or those spots)? The 230-pound Gaskins provides a physical element that Buffalo's running game has lacked, but both Choice and Brown have also had their moments during training camp. All three could see extensive work as the team's top two backs are saved for the regular season.

Wide Receiver

The battle is on for, in all likelihood, two wide receiver positions at the back end of the depth chart. A player many consider a lock for one of those spots, Brad Smith, is not likely to play after missing practice Friday. Another top competitor, Kevin Elliott, will also miss the game with a shoulder injury. That puts four popular receivers - Da'Rick Rogers, Chris Hogan, Marcus Easley and Brandon Kaufman - at the forefront of this race in Indy. All are likely to see significant playing time, and there will be plays to be made.

Tight End

If the Bills are going to keep a third tight end, one of the team's project depth players will need to step up with a strong preseason. Mike Caussin (hip) has missed a lot of practices this summer for what feels like the fifth straight year, so on Sunday, the likes of Chris Gragg, Dorin Dickerson and the recently-signed Nick Provo (a Syracuse grad) will look to make a positive impression - not just as pass-catchers, but on special teams, as well.

Offensive Line

Chris Hairston remains on PUP with a back injury, so a lot of second- and third-team offensive linemen will be showcased as the Bills try to figure out the back third of their offensive line depth chart. Thomas Welch, Sam Young, Tony Hills and Zebrie Sanders are the names to watch at tackle (Welch and Young in particular), while inside we're concentrating on David Snow, Keith Williams, Antoine Caldwell and Zack Chibane (Snow and Caldwell in particular). Of those eight players, as many as three could make the final roster.

Defensive Line

Several of Buffalo's young depth players along the defensive line have flashed ability in the camp setting - and with the depth situation murky, players like Torell Troup, Corbin Bryant and Jarron Gilbert will be trying to make a strong impression in their bid for one (or, if they're lucky, two) defensive line spots on the roster. Troup and Bryant, in particular, have looked solid for stretches, while the more versatile Gilbert has been nicked up a bit.

Linebacker

The front end of Buffalo's linebacker depth chart is more settled than it might have been given the team's inexperience at the position, but the back end remains something of a mystery. Marcus Dowtin and Kourtnei Brown are the names to watch in terms of edge linebackers (Brown is a pass-rusher, Dowtin more of a strong-side player in the mold of Manny Lawson), while Bryan Scott, Arthur Moats and Chris White are worth paying attention to inside. It's not inconceivable that all of these players will make the team; then again, they might not.

Secondary

Given Mike Pettine's proclivity for multiple looks, disguised coverages and blitzing defensive backs, 10 members of the secondary on the 53-man roster may even be a conservative guess (a number which, for now, should include safety Jairus Byrd). We'll be watching Nickell Robey (a likely first-teamer in Indy), T.J. Heath and Crezdon Butler at cornerback, along with rookie Jonathan Meeks and Dominique Ellis at safety. When push comes to shove, those look like the biggest names competing for deep roster spots in the secondary.

Are there any other situations at the back end of the roster that you'll be keeping an eye on? (We left Jeff Tuel for y'all to discuss, for example.)