Williams left Buffalo's Week 3 loss to San Diego after aggravating the injury. He's been limited since training camp with the back injury and did not practice all week.
Rookie Cyril Richardson has lined up in Williams' place at left guard at practice and is the favorite to start against Houston. Though Bills coach Doug Marrone said Buffalo may use both Richardson and veteran Kraig Urbik at left guard.
''We may split them a little bit and rotate them in there,'' Marrone said.
Wide receiver Marquise Goodwin (concussion) is also out.
Linebacker Keith Rivers is expected to play for the first time since Week 1 after suffering a groin injury in Buffalo's season opener. Rivers and safety Da'Norris Searcy (ankle) were limited Friday, but are listed as probable.
Cornerback Ron Brooks is probable after missing Friday's practice due to illness.
Wide receiver Marcus Easley (knee) and linebacker Randell Johnson (knee) are out.
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