The England winger will return to his old club in a deal until the end of the season, with the German giants paying just £3million in a loan fee and to cover part of his wages.

Dortmund returned from their winter break in Marbella on Tuesday and they travel to Darmstadt on Saturday evening for a Bundesliga clash — although the England international is unlikely to feature.

He has not played for United since August and was frozen out of the squad after a huge fall-out with chief Erik ten Hag.

Sancho, 23, was at Dortmund from 2017 to 2021, making 137 appearances for the club and recording 50 goals.

Yet in his two and a half seasons in Manchester, Sancho only managed a paltry 12 goals and six assists in 82 appearances.

Initially, Dortmund officials did not want to make a move for Sancho who was notorious for poor timekeeping before moving to Old Trafford for £73m in 2021.

But as the club is currently struggling in fifth place, Dortmund decided bringing Sancho back was a risk worth taking with United paying a third of his £290,000-a-week salary.

And Saha reckons Sancho’s United stay has been an expensive waste.

The ex-France forward said: “Jadon is one of United’s biggest transfer failures — you can’t have that type of quality sidelined because of his mindset. You can’t leave him out for six months because of that.

“The only thing that should stop you is injuries.

“We know he is good enough, which is why it doesn’t sit right.

“You can’t be putting yourself in that situation and thinking that you are bigger than the manager.

“Whatever happens, I don’t back Sancho — which is hard for me as a supporter of United. It’s just horrendous.”