Wells missed Tuesday's practice after aggravating the injury on Monday, McCarthy said after Tuesday's practice. Wells injured the back early in camp and returned to play against San Francisco on Aug. 16, only to injure a muscle on the other side of his back. Monday was Wells' first practice since that game.
"I think it was 16 days that he had been doing through the rehab, and it's unfortunate," coach Mike McCarthy said. "I know Scott's frustrated."
That means the line shuffling that marked much of training camp was present again. The line on Tuesday was the same as the group that started last week's preseason finale against Tennessee: Chad Clifton at left tackle, Daryn Colledge at left guard, Jason Spitz at center, Tony Moll at right guard and Mark Tauscher at right tackle. Spitz started at right guard on Monday, and was replaced there by Moll.
Wells' setback just adds to the challenge of facing the Vikings' stalwart defensive line, led by end Jared Allen and tackles Pat Williams and Kevin Williams.
"Probably the best defensive tackle tandem that we'll play," McCarthy said. "But that's why we practice the way we've been practicing with our offensive line. They give us the flexibility to go into a game with seven offensive linemen."
Running back Ryan Grant sat out practice, too, though McCarthy said "he'd be surprised if he doesn't practice Thursday." The Packers do not practice on Wednesday.
Grant, who missed the first three preseason games with a hamstring injury and didn't touch the ball during a cameo appearance in the finale against Tennessee, wore his No. 25 jersey and shorts while his teammates labored through a steamy midday practice on Clarke Hinkle Field. McCarthy said Grant had "soreness" in the hamstring, and the back watched as a precautionary reason.
Also held out of practice was defensive end Kabeer Gbaja-Biamila, receiver James Jones, guard Josh Sitton, linebackers A.J. Hawk and Tracy White, safety Charlie Peprah and defensive end Jeremy Thompson. Clifton took part in the jog-through practice before departing for treatment.
Back in the starting lineup was safety Atari Bigby, who turned an ankle at Denver in the third preseason game.
McCarthy didn't rule out Hawk or Jones for Monday. Neither have practiced this week, and Jones continues to wear a brace on the right knee he injured against San Francisco.
"A.J. has done exactly what we all thought he would do," McCarthy said. "He's way ahead of schedule, and that's the problem that you have when you have to make these types of decisions. The doctor has a criteria of what he thinks the time frame may be, and then you have the individual, who has no history of being injured, and just attacked it."
Bill Huber is editor of Packer Report and PackerReport.com. E-mail him at firstname.lastname@example.org