Bulaga suffered the injury Saturday night during a 64-play scrimmage, and team doctor Patrick McKenzie discovered the extent of the damage on Sunday. Bulaga's father said the tackle is sending his MRI to Dr. James Andrews for a second opinion.
"We're waiting to see what he has to say," said Joe Bulaga. "Bryan said it feels good and he was able to finish the drills (after the injury). Right now we're just sitting and waiting."
If Andrews confirms the ACL tear and Bulaga is indeed out for the year, it will be a serious blow to the Packers' offensive line. Over his first three seasons with Green Bay, Bulaga played in 37 regular-season games, starting 33. He played in every game during his rookie campaign, but he missed four games in 2011 and seven games in 2012.
The Packers are expected to move rookie David Bakhtiari into Bulaga's spot, according to McGinn. Green Bay selected Bakhtiari in the fourth round of April's NFL Draft, and he's already impressed coaches at training camp.