Seattle coach Mike Holmgren said that test results showed a virus and Graves' disease caused Bobby Engram's hyperactive thyroid and, subsequently, an accelerated heartbeat and fatigue. Engram has lost about eight pounds while staying at home for the last two weeks. Friday, the team's leading receiver in 2005 rode an exercise bike and then appeared at practice for the first time since he got sick. Engram exchanged hugs on the sidelines with fellow receivers Deion Branch and Darrell Jackson. He appeared in good spirits -- and thinner. When asked whether Engram had missed so much time that he may need a couple of weeks of conditioning before he can play, Holmgren said, "I hope it's not a couple of weeks. I'm going to stick him in there as soon as I think he's ready to go."