The news will come as a further boost to Ulster's new head coach Mark Anscombe, following his side's 18-10 win over Glasgow Warriors in the opening round of the league.
Rory Best and Chris Henry are still unavailable because of the IRFU's player management programme but are expected to make a return in the coming weeks.
Meanwhile, young centre Nevin Spence has returned to full training after injury but will not be considered for this weekend's trip to the Liberty Stadium.
ULSTER Squad (v Ospreys) - Backs (12): Paul Marshall, Michael Heaney, Niall O'Connor, Paddy Jackson, Luke Marshall, Chris Farrell, Darren Cave, Michael Allen, Craig Gilroy, Andrew Trimble, Peter Nelson, Jared Payne.
Forwards (16): Rob Herring, Niall Annett, Nigel Brady, Adam Macklin, Declan Fitzpatrick, Callum Black, Tom Court, John Afoa, Lewis Stevenson, Neil McComb, Johann Muller, Mike McComish, Stephen Ferris, Robbie Diack, Sean Doyle, Nick Williams.