Ayew to miss Champions League opener
"Andre Ayew will be out for 10 days after injuring his groin while on international duty," the Ghana FA said on their website on Thursday.
"The Marseille player injured his groin during Ghana's Nations Cup qualifier at home to Swaziland last Friday."
Ayew will also miss Saturday's Ligue 1 home game against Stade Rennes.
Marseille were drawn with Olympiakos, Borussia Dortmund and Arsenal in Group F.