Lock Neil McComb and hooker Nigel Brady also return to the panel.
Number 8, Nick Williams, is included in the squad despite having suffered a rib injury in the 25 points to nil win over Connacht. He is responding well to treatment and a decision on his fitness will be made later in the week.
Prop Declan Fitzpatrick aggravated a medial ligament injury in training last week and remains unavailable for selection.
Australian-born flanker, Sean Doyle, suffered a broken leg playing for Dungannon on Saturday and will be out for up to six weeks.
Tickets for the match are still available. Please call the Ravenhill Ticket Office on 02890493222 (option 2) or visit www.ulsterrugby.com to buy tickets.
Provisional Ulster Rugby squad to face Castres Olympique, Fri 12th October, Ravenhill (8.00pm):
Rob Herring, Rory Best, Nigel Brady, Neil McComb, John Afoa, Tom Court, Adam Macklin, Callum Black, Johann Muller, Dan Tuohy, Lewis Stevenson, Stephen Ferris, Mike McComish, Iain Henderson, Chris Henry, Nick Williams.
Ruan Pienaar, Paul Marshall, Michael Heaney, Paddy Jackson, Paddy Wallace, Darren Cave, Luke Marshall, Andrew Trimble, Tommy Bowe, Craig Gilroy, Jared Payne.
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