This is the second of three matches in six days in a "difficult week" but Jose will resist the temptation to rest key players ahead of his Stamford Bridge return and next week's cup tie with City.
"It's a very difficult week for us, Monday, Thursday, Sunday: Liverpool, Fenerbahce, Chelsea, so it is tough and we have to be ready.
"The opponent is good with experienced players so if we play with a team that is not good and strong, we won't have a chance.
"We will play a really good team knowing two days later we have play again but that is football.
"It is a big test for everyone but we have to expect that at Manchester United."
Mourinho added that he is "counting on his captain" but did not say that Rooney would start.
It was against Fenerbahce that Rooney burst on to the Old Trafford stage as a fresh faced 18-year-old when he put them to the sword with a debut hat-trick in a 6-2 Champions League thumping in 2004.
Luke Shaw returned to the fray late on at Anfield and will feature, while Henrikh Mkhitaryan, who has not played since the derby, is fit again and in contention for involvement.
Anthony Martial and compatriot Morgan Schneiderlin have both recovered from knocks and are pushing for recalls but there are no fresh injury worries for United.
Former Sunderland boss Dick Advocaat is now in charge at the SuperLig club and despite an indifferent start to their domestic campaign, they currently lead the way in Europa League Group A.
They left it late to salvage a point in Zorya on Matchday One before a 1-0 win over Feyenoord last time out saw them go top of the standings, one point ahead of us.
This tie sees a familiar face return to Manchester in former United striker Robin Van Persie.
The Dutchman was a key man in Sir Alex's last title winning season at the club and scored just shy of 50 goals in his three seasons at Old Trafford.
30 of those came in a prolific first campaign at United and his memorable hat-trick against Villa sealed the league crown and made him a domestic champions for the first time in his career.
Welcome back Robin!
Alongside RVP in the visitors ranks are ex Liverpool man Martin Skrtel and forward Jeremain Lens also plays for the Istanbul outfit under his former Sunderland boss Advocaat.
Form guide: United L W W W D D Fenerbahce D L W W D D
Match odds: United 7/5 Draw 10/11 Fenerbahce 11/2
Referee: French official Benoit Bastien is the man in the middle.