Dan Biggar lines up at fly-half for the Probables who include the uncapped Jordan Williams on the wing in the absence of Lions flyer George North.
Lions backs Mike Phillips, Jamie Roberts, Jonathan Davies and Alex Cuthbert all start for coach Howley's Probables, with Gethin Jenkins, Ken Owens and Adam Jones in the front-row.
McBryde's Possibles side features two uncapped players in the starting pack, in Scarlets prop Rob Evans and former Wales Under-20 skipper Ellis Jenkins.
James Hook will pull the strings for the possibles at fly-half and Howley cannot wait for the competition for places to reach fever pitch.
"Friday is a huge opportunity for players and a chance for us to see them go up against each other for the Wales jersey," said Howley.
"It's something we haven't been able to do for the last decade, but it will be a big night for the players, we want to see them in a pressured environment and that's what we will get on Friday."