"Matt is resting," Harbaugh said Friday. "He had some back spasms, too. It's probably both me and Matt. Matt has had the back spasms, but I am going to probably slow him down a little bit more, especially this week, and then maybe next week after the game, we will get him back a little bit more."
Birk, the 36-year-old center who is in the midst of his 15th training camp in the
In 2010, he played despite a swollen knee that had to be drained at least once a week. He sat out a good portion of last year’s preseason after undergoing surgery on his left knee. Birk was absent from a few minicamps this past offseason after undergoing surgery to repair varicose veins in his