Panthers' quarterback David Carr missed practice for a second straight day Thursday with a sore back, increasing the chances 43-year-old Vinny Testaverde could start on Sunday at Arizona. Testaverde, signed on Wednesday, and undrafted rookie Matt Moore, signed just over a month ago, took all the snaps in practice for the banged-up Panthers. Coach John Fox wouldn't say which QB he'd use if Carr can't play Sunday.