The clubrefused to comment when contacted by Reuters.
Ronaldo, whomissed matches in January and March with hip flexor trouble, is United"s topscorer this season with 24 goals in all competitions.
United aresixth in the league on 58 points, two points above seventh-placed West HamUnited, and they need a win at Selhurst Park to be certain of securing a placein next season"s Europa League.
Sunday"sgame will be Ralf Rangnick"s last as the interim manager, with Erik ten Hag setto be the permanent manager from next season.
