Scrum half Paul Marshall, prop Justin Fitzpatrick, lock Justin Harrison and flanker David Pollock have been omitted from the squad for this weekend's game. Marshall has a groin injury.
The seven other players who have made the cut of 25 are back-line duo Kieran Campbell and Paul Steinmetz, while up front, Declan Fitzpatrick, Carlo Del Fava, Kieron Dawson, Grant Webb and Ballymena clubman Chris Henry could force their way into the starting line-up.
Commenting on how training has gone this week at Newforge, Ulster assistant coach Steve Williams said: "Training has been good this week. We have taken a good look at ourselves and picked ourselves up again and begun to move on (from the Munster match).
"This is a learning curve and the game against Munster was a reality check, but it wasn't all negative. There were some big positives from the game as well as the negatives.
"Morale is fine in the camp. It will probably take the lads some time to get over the disappointment of not performing as they know they can. That is what will stick in their stomachs, so they just want to get out there this weekend and put it right."
Giving his opinion on Friday's opponents the Ospreys, the Welshman added: "The Ospreys have a fantastic squad with some great players and are currently right up there in Europe, and they are a hell of a good side."
ULSTER Squad (v Ospreys): Forwards (14) - Bryan Young, Declan Fitzpatrick, Nigel Brady, Rory Best (capt), Tom Court, Matt McCullough, Carlo Del Fava, Ryan Caldwell, Kieron Dawson, Roger Wilson, Neil Best, Stephen Ferris, Grant Webb, Chris Henry.
Backs (11) - Isaac Boss, Kieran Campbell, Paddy Wallace, Niall O'Connor, Mark McCrea, Rob Dewey, Mark Bartholomeusz, Andrew Trimble, Bryn Cunningham, Tommy Bowe, Paul Steinmetz.