Toulouse backs coach Jean-Baptiste Elissalde has confirmed that the Top 14 club's fly-half Luke McAlister will be sidelined for a month with a torn muscle.
McAlister sustained the injury in last weekend's Heineken Cup win over the Ospreys.
He had already been ruled out of the return match in Swansea this weekend.
The 28-year-old's place in the starting XV will be taken by Jean-Marc Doussain, who replaced him in the 63rd minute of his side's 30-14 victory in Toulouse.
McAlister has played in 13 of Toulouse's Top 14 and Heineken Cup matches this season, scoring 176 points.