Wout Weghorst will not be available for Saturday's Manchester derby as United have not yet completed a deal for the Burnley forward.
Erik ten Hag had been keen to have the Netherlands striker available for the home game against Manchester City, with a Cristiano Ronaldo shaped hole left in his United squad after his departure last month.
United needed to have registered the Dutchman by 12pm on Friday in order to include him in the squad, but the transfer has been slowed as Weghorst needed to cancel his loan at Besiktas before moving to Old Trafford. "I think we are close," Erik ten Hag said of a deal. But he wouldn't be available for tomorrow."
Asked about a potential striker shortage, Ten Hag said: "Weghorst wasn't even available in the last weeks, it would be a bonus if he was. We have won a lot of games without Anthony Martial."
Ten Hag has challenged his Manchester United players to show they have closed the gap on local rivals Manchester City in Saturday's derby. United were humiliated 6-3 at City in the last derby meeting back in October, with Ten Hag admitting his side were taught a lesson by Pep Guardiola's champions.
Since that defeat, United have been almost flawless, winning 15, drawing two and losing just one game in all competitions, rising from bottom to fourth place in the table.
Against that backdrop, Ten Hag said his players must prove how far they have come since that derby debacle when they host City at Old Trafford on Saturday.
“It's a question we have to prove tomorrow on the pitch,” said Ten Hag. “There is only one truth - always on the pitch. Tomorrow we have to do better.
“It was a lesson and we took that lesson and from that point on we made huge progress, so we have to continue the progress. We know what we have to do work on. It's not only coming overnight.
“There was a process in the last months and now we have to face it against the better teams. It's about the mental approach and attitude, so we have to be brave, act with belief and play our game.
“This period of the season is about getting yourself in a position to win trophies at the end of the season, nothing else, so go from game to game. That game against City was a setback. We can all find reasons why, but always you have to act, to deliver, as a manager, as a coach, you have to go to certain steps.”