"Going into this game we feel like we know Anthony certainly a lot better than we know Adrian," said head coach Dick Jauron. "Also, because Anthony had the back spasms we'll probably play Adrian a good deal more and possibly even start him with that first group just because we'd like to see him.
The possible start came as news to Peterson.
"I didn't have an idea about it, so I wasn't even thinking about it," Peterson said. "Whenever I get in I'm going to do my thing. I'm going to go hard anyway."
This doesn't mean that Peterson has overtaken Thomas as the starter, but it isn't out of the realm of possibility.
"Anthony is our starter right now," Jauron emphasized. "There are starters now and by the opening game the players will decide who holds that position. That will be true everywhere."
Peterson worked extensively with the first team when Thomas missed three days of practice because of back spasms. In many ways Peterson is a work in progress. As a rookie he carried the ball 19 times for an average gain of 5.3 yards. Therefore there is still a feeling out process of what Peterson is capable of.
"We feel like we know him a little bit, but again we didn't see Adrian in a lot of game competition a year ago," Jauron said. "So, we'll take a good look at Adrian in the preseason."
Aaron Gibson would have been ready to go if the Bears were playing a game Tuesday, but they weren't, so he sat out of practice.
Although Gibson's MRI showed no major damage, the right tackle has been slowed by swelling in his knee following practice Monday morning. The team is now considering working Gibson in morning practices and resting him in the afternoon sessions.
The setback is a disappointment to a team that already lost one starter, in Marc Colombo, and is trying to build continuity with a new quarterback.
"Given what we had seen he had really done a terrific job to that point," Jauron said. "It was a disappointment. Hopefully he won't go backwards when he comes back on the field he'll proceed from where he left off. He was doing very well."
Haynes injury is particularly frustrating because every day he sits is another he falls further behind the rest of the defense.
"He needs to be on the field obviously, they all do, but the younger the player more he needs to be out there," Jauron said.
The immediate impact of Gibson's injury is that Steve Edwards, who has never played a snap at tackle in the NFL, will get more reps with the first team, which should help speed up his development.
"It's a good opportunity," said Edwards. "You never want to see anybody get hurt, but it's a great opportunity for me right now.
"I could possibly start or get some playing time. It's huge for me, especially at this point of my career."