Posted by ESPN.com's Mike Sando
MEQUON, Wis. -- Injury problems are severely hurting the Seahawks and Cardinals at center. The Rams are a bit unsettled there, too, as they wait to see how the battle between Richie Incognito and Brett Romberg settles out.
The 49ers' Eric Heitmann is easily the most proven center in the division. Smart veteran centers can be crucial in sorting out pre-snap assignment changes based on what they see from the defense. More pressure falls on the quarterback when the center isn't able to make adjustments on the fly. Here's a look at how the position shakes out in the division:
Seattle: The team still hasn't found a reliable replacement for Robbie Tobeck, who retired after the 2006 season. Chris Spencer has the talent, but injury problems are affecting the 2005 first-round pick. Spencer has had multiple shoulder surgeries. He's currently missing time with a back problem. Worse for Seattle, backup center Chris Gray also remains sidelined with back trouble. Backup guard Mansfield Wrotto, a fourth-round choice in 2007, is working with the starters in camp. The team expects Spencer to be ready for the season, but he needs reps.
Arizona: Al Johnson underwent knee surgery recently. He could be out until the first or second game of the regular season. Backup Lyle Sendlein has some experience, and line coach Russ Grimm should be able to make this work for the time being. But with third-string center Scott Peters possibly lost for the season, the Cardinals' margin for error is slim. The team lacked line depth even before Johnson went down.
St. Louis: Romberg is the incumbent, but the team is giving Incognito a chance to win the job in camp. If Romberg prevails, Incognito probably becomes the starting right guard. Mark Setterstrom is also in the mix at right guard. Former Cardinals backup center Nick Leckey is also in camp with the Rams.
San Francisco: Heitmann remains a steady, mostly durable starter for the 49ers. He suffered a broken leg late in the 2006 season, but came back to start every game in 2007. Teammates have voted him the 49ers' best lineman the last two seasons. Heitmann is a former starting guard. He made the full transition to center for the 2006 season.
The Rams are back on the practice field in another 45 minutes or so. I'll file some notes afterward.