Coach Jose Mourinho slammed the state of the Rostov pitch on Wednesday ahead of Manchester United's Europa league tie, questioning whether the game should go ahead.

"It's still hard for me to believe that we are going to play," Mourinho said at a press conference in Rostov ahead of Thursday's last-16 tie.

"I know that we have to, but it is hard for me to believe we are going to play on that field -- if you can call it a field."

Mourinho compared the pitted and damaged Olimp-2 stadium pitch in Rostov to the surface at Beijing's Bird's Nest Olympic Stadium where Manchester United and City refused to play a pre-season friendly last year.

"I have now a lot to think (about) because I was expecting something more playable.

"On a very similar pitch in the summer in China, me and Manchester City decided not to play, but it looks like we have to play."

He said he spoke of the risks of playing on the surface to a UEFA official and was rebuffed.

"I didn't have any contact with anyone until now. I just had a quick contact with gentleman from UEFA when I was looking at the pitch," he said.

"When I told him about my concerns the gentlemen just told me the players are insured -- if something happens no problem."

Concern about the uneven pitch and his players' safety posed a team selection headache for the Portuguese coach.

"I don't know which team to play, really," he said, against a side he described as 'dangerous', and who he knows beat both Ajax and Bayern Munich this season.

Wayne Rooney and leftback Luke Shaw were left at home along with Bastian Schweinsteiger and United are without Eric Bailly, who was sent off in their round of 32 1-0 win at Saint-Etienne.

But Armenian forward Henrikh Mkhitaryan returns to the 20-man squad after recovering from an injury incurred just after scoring the winner at St Etienne.

United's target-man Zlatan Ibrahimovic is available and will play, Mourinho confirmed, despite his three-match domestic suspension which does not apply to the Europa league.

Mourinho is pondering how to counter a strong Rostov attack n which he singled out Iranian striker Sardar Azmoun as a particular threat

"I don't even know if he plays. I think Rostov have four good attack players, especially three of them that are very dangerous so I don't know who is going to play," he said.

"I know that they are dangerous, I know they defend with 10 players, they defend with everybody and then they are very dangerous in conter-attack."

Rostov coach Ivan Daniliants promised a "classy performance" against United.

"The match is sold out and we're set to give our fans a classy performance," he said.