Matt Tobin competed at RG -- by playing LT

Matt Tobin's work at left tackle on Monday potentially sets the right guard up to be a swing player on the Eagles' offensive line. Drew Hallowell/Getty Images

PHILADELPHIA -- It wasn’t that surprising that Andrew Gardner started at right guard against the Indianapolis Colts Sunday. Philadelphia Eagles offensive line coach Jeff Stoutland has been rotating players at that vacant position, and it was Gardner’s turn.

“He just rotated,” coach Chip Kelly said. “It wasn't a separation (from the pack). I think it was just who we had in there the last day or so. We are going to give all those guys an opportunity before we make a decision on what's going to go on there.”

The bigger surprise was that Matt Tobin, one of the prime competitors for the right guard job, played 60 percent of the offensive plays -- at tackle. It was unclear whether that was merely an anomaly created by Stoutland’s rotation system, or if Tobin is being prepared to be a swing player.

On regular-season game days, the Eagles usually have seven or eight offensive linemen active. There are the five starters, who specialize in one position, and two or three backups. One of the backups can play both guard and tackle. One can play both center and guard.

That means being able to play three or four positions -- center and both guard spots, or both guard and tackle positions.

Last year, Gardner began the season as the guard/tackle backup. He replaced Allen Barbre at right tackle in the season opener and moved to guard when Evan Mathis and Todd Herremans were injured.

Tobin played only at guard last season, but he is capable of playing tackle. His playing tackle Sunday could mean the coaches are preparing him for that swing spot, which could in turn mean that Tobin is behind in the right guard competition.

Gardner and the rest of the starting offensive linemen played only 11 plays against the Colts. John Moffitt and Julian Vandervelde each played 61 plays, or 76 percent of the offensive plays. Moffitt appears to be very much in the mix for the right guard spot.

It will be telling who lines up with the first team Tuesday, when the Eagles return to practice at the NovaCare Complex. And it will be interesting to see how playing time is allotted when the Eagles practice with the Baltimore Ravens Wednesday, Thursday and Friday. Finally, it will be significant which player starts at right guard in Saturday night’s preseason game against the Ravens.

With Sam Bradford scheduled to make his preseason debut, the coaches will want the best possible line in front of him.