4. Colts offensive line
There's a good chance we see a little of left guard Quenton Nelson and center Ryan Kelly in the season opener. Starting right tackle Braden Smith will likely rest given his recent flare-up in his knee. This leaves us with left tackle Bernhard Raimann and right guard Will Fries as the only starters who will see decent playing time. Both are still proving themselves as NFL players, especially Fries, so they'll have more oppotunities than the aforementioned veterans who clearly belong in this league.
Although the main concern is that of the starting group returning to form, depth on Indy's OL remains a big question mark. I, of course, would like to see the starters hit the ground running as if they're back to their top-five selves, but I'll be more focused on the young starters and the backups that follow.
The Bills defensive line will provide a great test for any OL they face in the preseason as they have one of the deepest lines in the league. If the young starters and the backups that follow stand their ground against a formiddable unit such as Buffalo has, I will feel much better about Indy's depth across the offensive line moving forward.