Wallace played at out-half and scored all his side's points in their 19-18 home defeat by Edinburgh.However, with David Humphreys returning to the side and Bryn Cunningham impressing at full-back, Wallace has to content himself with a place on the bench.
Adam Larkin comes in for Ryan Constable in the centre with the injured Sheldon Coulter replaced by James Topping.
Up front, Justin Fitzpatrick is in the starting lineout, Jeremy Davidson returns form injury, and with Andy Ward still out with an ankle injury, Jonathan Bell continues with the captaincy.
Commenting on the selection, coach Alan Solomons said, "Swansea have a big physical presence in the back line spearheaded by Scott Gibbs and I feel the changes we have made will give us more physical presence."" In the front row, Justin came in for the second half of the Edinburgh gameand played extremely well, so he will start against Swansea, who have a strong pack that scrummage well."
Ulster.Bryn Cunningham; James Topping, Jonathan Bell (Capt), Adam Larkin, Tyrone Howe; David Humphreys, Neil Doak; Justin Fitzpatrick, Matt Sexton, Robbie Kempson; Mark Blair, Jeremy Davidson; Warren Brosnihan, Neil McMillan, Russell Nelson,