The Bills were apparently caught by surprise when Mario Williams had a procedure on his injured wrist last week. 

Chris Mortensen from ESPN.com cites team sources telling him that Williams did not show up at Ralph Wilson Stadium last Monday and later texted a trainer and Defensive Line Coach Giff Smith to let them know he was getting a second opinion on his wrist.

Another text from Williams informed them he was having arthroscopic surgery on the wrist.  In the text, Williams also let them know he would be back for practice Monday(today) and expects to play Sunday at Houston.

Williams, in the first year of a six year, $100 million contract, has 3.5 sacks in seven games.