Vikings coach Mike Zimmer opened his press conference this afternoon by announcing that center John Sullivan is unlikely to return this season after having a second surgery on his back recently.

"He had a relapse about 10 days ago in the weight room and he had another procedure done on his back," Zimmer said. "We don't know when he'll back or if he'll be back [this year]."

Sullivan injured his back during the preseason and had surgery before the start of the regular season. He was placed on injured reserve with the designation to return. He was eligible to return in Week 9.

"It was disappointing," Zimmer said. "He was doing really, really good and then all of a sudden had a little mishap."

Asked what the chances are of Sullivan being able to return this season, Zimmer said, "Probably minimal."

Backup Joe Berger has started the first six games and will continue as the starter as long as he's healthy.

"I think he's done good," Zimmer said. "One of the things that we tried to emphasize this past week with the offensive line was keeping our pad level lower. We improved this week doing that. And consequently we were lower on our play-action passes which helped to get some guys open downfield and get Teddy a little more time.

"But as far as Joe specifically, I thought he's done a good job. He's getting guys for the most part in the right place. We've had a few mishaps here and there when we've had the wrong assignments. But overall he's done a good job."