Manchester United interim manager Ralf Rangnick has said his players are focused on their FA Cup tie with Middlesbrough despite the ongoing police investigation surrounding striker Mason Greenwood.

United clarified on Thursday that Greenwood remains unavailable "until further notice" after the 20-year-old was released on bail on Wednesday after he was questioned by police on suspicion of the rape and assault of a woman.

Rangnick said the situation has been a "topic within the team" during training this week but insists the squad are ready for their FA Cup fourth round tie at Old Trafford on Friday.

"We had a good normal week of training with five training sessions including today's training," Rangnick told a news conference on Thursday.

"Obviously, it was a topic within the team but they're human beings and Mason was part of the group before we had our break.

"It was a good week of training, we could train under normal circumstances and we are looking forward to the game tomorrow."

Greenwood, 20, was initially arrested on Sunday on suspicion of rape and assault following the circulation of images and an audio file on social media.

He was further arrested on Tuesday on suspicion of sexual assault and making threats to kill.

Rangnick said Greenwood's ongoing absence from the squad had played a part in the club's decision to block Jesse Lingard's proposed move to Newcastle United on deadline day.

"Three weeks ago Jesse didn't want to leave, then he changed his mind," Rangnick said.

"I had a chat with him 10 days ago and I could fully understand why he wanted to leave to get game time for his future and the World Cup and I told him if he finds a club and the club find a solution with our club I would allow him to leave.

"The board told me they couldn't find an agreement with any clubs interested in him.

"With the window closing Monday evening, the board informed me they would rather he stay. We had a problem with Mason Greenwood, being without a player for the time being and the club not finding an agreement with another club."

Lingard will not be available to face Middlesbrough after Rangnick said the 29-year-old had not trained this week after being given time off to "clear his mind."

However, Paul Pogba could start a game for the first time since November after recovering from a thigh injury.

"Paul will be part of the group he might even be in the starting XI," Rangnick said.

"Edinson Cavani will only return at the weekend. He contacted me at the weekend and asked to have two more days at home. I knew he couldn't be in the starting XI with jet lag anyway.

"Victor Lindelof has been ill the whole week and not training. The same is true with Jesse, he asked if we could give him a couple of days off to clear his mind. He will be back in training on Monday and part of the whole squad.

"Eric Bailly came back yesterday, he has some problems with his ankle and will not be part of the squad. Luke [Shaw] will be playing because Alex Telles played 90 minutes for Brazil."