Joe Mauer (quad) isn't sure when he'll be able to return to the lineup. Mauer was making solid progress earlier this week in his recovery from a right quad injury, but he's stalled lately. The Twins were hoping he'd be able to catch in the bullpen Thursday, but he wasn't feeling up for it. "It's not much better than yesterday," Mauer said Thursday. "I thought I'd be able to do a little bit more. It's real frustrating." Mauer seems unlikely to be ready to play Friday, with his status for the entire weekend series in Cincinnati up in the air.