(photo Via @Dmac1043)
Yes, Peyton Manning's practice jersey has a big ass Buick patch on it. Players are allowed to display sponsor names during practices, although we can't recall having seen any of them actually do it before now. Folks down at Dove Valley say that it's actually pretty common.
The NFL still hasn't sold uni space for corporate advertising yet - and Roger Goodell remains firm that the league won't. Estimates are that owners are leaving $100M on the table for not doing so.