Talking out Friday's match, Matt Williams said: "The Ospreys are a fantastic team, a brilliant team and physically they are a massive side.
"No-one expects us to win. Everyone has written us off, everyone says we can't do it, so this is a week when there is not a lot of pressure on us, and that is a good thing," said Williams.
Not considered due to injury: Stephen Ferris, Bryn Cunningham, Paul Steinmetz.
Although tickets for the Main Stand and Terrace have now sold out, there are still tickets available for the Ulster v Ospreys match, within the Promenade and YellowTom areas of Ravenhill's grounds. A limited number will so be available to purchase on the gates on match night.
ULSTER SQUAD FORWARDS
Brendon Botha, Tom Court, Bryan Young, Ed O'Donoghue, Matt McCullough, Carlo Del Fava, Chris Henry, Nigel Brady, David Pollock, Rory Best, Ryan Caldwell, Robbie Diack
ULSTER SQUAD BACKS
Simon Daneilli, Andrew Trimble, Darren Cave, Cillian Willis, Niall O'Connor, Clinton Schifcofske, Ian Whitten, Isaac Boss, Ian Humphreys, Timoci Nagusa, Mark McCrea, Paddy Wallace