Baas limped off at the end of the Giants' opening 17-play drive with a knee injury and did not return. Baas said Sunday night that he was heading for an MRI to determine the extent of the damage.
"We think we have an idea what it is," Baas said. "Hopefully it's not what we think, but we'll see. Obviously it's frustrating, because you feel like you can't catch a break. But it is what it is."
Baas did not indicate what he and the Giants think the injury might be despite, speculation that he tore a ligament.
The injury, however, means that Jim Cordle returns to the lineup. Cordle started three games in Baas' absence and played 58 snaps after Baas left the game.
If Baas has a season-ending injury, following a 2012 season during which he played poorly while battling a variety of injuries, that might call the veteran center's future with the Giants into question.
Baas has two years and $16.7 million remaining on a five-year deal. If the Giants were to part ways with him following this season the cap hit would be enormous, $6.45 million in 2014 and $3.225 million in 2015.