In team news, Keith Matthews will start for Connacht for the first time since September, having overcome a calf injury.
He is joined in Connacht's midfield by Mel Deane with Fionn Carr and Troy Nathan lining out on the wings.
Ian Keatley and Frank Murphy return to renew their half-back partnership while up front, hooker Sean Cronin is joined in the front row by Brett Wilkinson and Robbie Morris.
Michael McCarthy and Andrew Farley team up once again in the second row, while Ray Ofisa, Johnny O'Connor and Colm Rigney start in the back row.
Muldoon has joined Liam Bibo (calf), Michael Roberts (calf) and Aidan Wynne (shoulder) on the province's injury list.
CONNACHT (v Ulster): Gavin Duffy (capt); Fionn Carr, Mel Deane, Keith Matthews, Troy Nathan; Ian Keatley, Frank Murphy; Brett Wilkinson, Sean Cronin, Robbie Morris, Michael McCarthy, Andrew Farley, Ray Ofisa, Johnny O'Connor, Colm Rigney.
Replacements: Adrian Flavin, Ronan Loughney, Andrew Browne, Michael Swift, Kieran Campbell, Tim Donnelly, John Hearty.