A back injured forced center John Sullivan to miss his fourth consecutive practice in addition to Saturday night's third preseason game, but Vikings coach Mike Zimmer said after Tuesday's practice that he's not concerned.

"No, from what I understand, it's not anything serious," Zimmer said. "We're just being cautious with him."

Sullivan hasn't even been on the sideline for practice during the injury, but Zimmer said he has been in the building receiving treatment.

With former Texans center Chris Myers announcing his retirement today, Sullivan takes over the lead in consecutive regular-season starts among NFL centers. He's at 57 consecutive starts.

In other news, Zimmer announced that Gerald Hodges, a backup at both outside linebacker positions, will get the start at middle linebacker in the base defense in Saturday night's game at Dallas. Rookie second-round draft pick Eric Kendricks, who started last Saturday's game in the middle, will be the nickel linebacker alongside Anthony Barr.

The Vikings are using the third preseason game to continue looking at their different combinations at linebacker. Audie Cole started the first two preseason games in the middle. Chad Greenway has been with the first nickel unit, but Kendricks will handle that on Saturday.

Hodges has no regular season experience in the middle. But the Vikings are trying him there because some consider him their third best linebacker.

"No, from what I understand, it's not anything serious. We're just being cautious with him.