As good as Foster has been as a starter for the Steelers, the team has never seemed particularly sold on him as a long-term option at right guard.
I think Foster will once again find himself in competition to retain his starting job, although I'm not sure yet if that competition will be from a draft pick or from a veteran who's brought in during free agency.
Foster might very well win that competition, but you get the feeling that he may be the backup or the odd man out if anyone else shows some promise. The Steelers do need to improve their run blocking, particularly in the middle, so maybe the lack of faith in Foster is more well-founded than one might think.
Either way, on a team where so many aging veterans have found their way off the team, Foster is a younger guy that might simply have to fight once again to hold his spot.