I read an earlier report on PWInsider I think it was, and it was mentioned that Bret wouldn't appear at Wrestlemania 22, unless he get's an appology of Vince McMahon for the screwjob back in 1997, and we all know Vince he's not one to make appologies now, so the chances of Bret making an appearance seem slim...

But Vince could be a man, and say sorry to Bret if he really wants him at Wrestlemania 22, so anything is a possibility really