There may be better links out there, but here's the first one I found:
http://www.billsbackers.com/122703.htm
Ruben Brown A No-Show
Another element came to light before the game with the Patriots when it was announced that Ruben Brown was "excused" from the game. Bills coach Gregg Williams said that "personal reasons" were the factors that determined that they would allow him to miss his first game after playing 71 straight. Bills GM Tom Donahoe emphasized that Brown was not suspended, but "inactive."
Rumors have come out of One Bills Drive that Brown was unhappy with Bills offensive coordinator Kevin Gilbride and the play calling all season. In fact, one source claimed that Brown confronted Gilbride during the week. Brown did not practice all week with the Bills and said on his radio show early in the week that it would have been hard for him to get motivated playing the last game of the season.
This comes at a time when the Bills needed some final stand, one last show of support for not only their coach, who is likely to get fired next week, but also for pride. What Brown did to the Bills and his teammates was to abandon ship. He had enough of the coaching staff and decided to make a statement to everyone by quitting on the team. Brown, who was voted to the Pro Bowl for the 8th straight year, may have played his last game in a Bills uniform last week against Miami.