Dyer suffered a bruised quadriceps during a scrimmage two weeks ago and has missed every day of practice since the injury.
Petrino said Dyer "hasn't made the progress we had hoped," in recent days and still has swelling in the leg. Petrino said he's "still hoping" to have him back at practice early this week and perhaps have him available for the opener.
"I didn't say he was out," Petrino said with a smile. "We're still hoping."
But the next few days will be a key to seeing if they can get Dyer back on the field."He still has some swelling in there," Petrino said. "Today and tomorrow are big days to see if he'll be available."
A former two-time 1,000-yard rusher at Auburn, Dyer ran just 44 times for 223 yards and two touchdowns last season. He played in eight games but had his season cut short by an injury, which led to sports hernia surgery.
Petrino said it took him a little while to get back after the surgery but by the spring game Dyer looked healthy. He ran for 150 total yards - running for both teams - in the spring game.