With David Pollock, Ryan Caldwell, Bryn Cunningham, Matt McCullough and Rory Best all still unavailable for selection through injury, Tuohy's return is most welcome for Ulster.
Speaking after the province's home defeat to Edinburgh last Friday, stand-in captain Chris Henry said: "It's a very disappointed changing room, particularly after the highs of the Ospreys game.
"We just do not know how we lost that game, and we should not have.
"Connacht had a good win against Cardiff so we know we will have to bring another performance again to Galway and hopefully this time we will come out on the right end of the scoreline."
Brian McLaughlin will confirm his matchday 22 on Thursday afternoon.
ULSTER Squad (v Connacht): Backs (10) - Timoci Nagusa, Darren Cave, Andrew Trimble, Simon Danielli, Ian Whitten, Paul Marshall, Isaac Boss, Ian Humphreys, Paddy Wallace, Clinton Schifcofske.
Forwards (14) - Nigel Brady, BJ Botha, Bryan Young, Ed O'Donoghue, Andy Kyriacou, Dan Tuohy, Robbie Diack, Chris Henry, Stephen Ferris, Willie Faloon, Thomas Anderson, Neil McComb, Tom Court, Declan Fitzpatrick.