Shaffer has started the last two games.
Receiver Lawrence Cager, who is tied for the team lead with 19 catches, also might miss the game. Cager was dealing with a shoulder injury before hurting his ribs in last week's 20-17 double-overtime loss to South Carolina.
Coach Kirby Smart said Monday that Shaffer's status will be "week to week." Two more part-time starters at guard, Solomon Kindley (ankle) and Ben Cleveland (undisclosed), also have injuries but are expected to play.
Smart says starting cornerback Tyson Campbell (turf toe), who has missed three games, "feels like he's almost back" but could miss another week.