Q: Hi Ed, I was reading in the notebook that all three centers are playing well. Assuming Justin Hartwig is the starter, can Sean Mahan or Darnell Stapleton play other positions well enough to be the backup or maybe even beat out one of the starters?

Tom Kovalcik, Barrington, NH

BOUCHETTE: No, they won't beat out a starter but, yes, each plays guard as well as center. If Hartwig wins the starting job at center, either Mahan or Stapleton will dress for games as the backup to both center and guard. The Steelers normally dress seven offensive linemen for games -- five starters and two backups. It's essential the backups have "position flexibility,'' as coach Mike Tomlin puts it so often. Each of the three centers can play two positions. Now, for the backup tackle. Do you go with Max Starks, who can play either tackle, or with Trai Essex, who can play either tackle and guard? It will be an interesting decision when it's first made on Sept. 7.