Ex-Sunderland midfielder Jan Kirchhoff opens up on 'huge mistake' not to sign Yann M’Vila from Rubin Kazan

The French midfielder made a positive impact during a loan spell at the Stadium of Light under Sam Allardyce but wasn't signed permanently following the appointment of David Moyes.

According to Kirchhoff, Sunderland turned down the chance to sign M'Vila from Rubin Kazan, instead deciding to spend the money on Didier Ndong.

"Definitely a huge mistake," Kirchhoff told the Roker Rapport podcast.

"I’m not scared to say what I think openly and it was a massive mismanagement that summer of transfers.

"We spent a lot of money, I read a lot about how we didn’t and how we didn’t have the support of the owner but we ended up spending something like £38 million on players.

"We bought players to replace other players. We signed a defender to replace Kaboul, a midfielder to replace Yann, we didn’t sign Yedlin on a permanent. You underestimate what losing senior players like Ola Toivonen and Wes Brown from the squad caused, too.

After escaping from relegation in the 2015/16 season, Sunderland looked well equipped to kick-on under Sam Allardyce.

But after their manager left to take charge of England at the end of season, Kirchhoff believes the quality at Sunderland dropped significantly.

"The squad’s quality dropped from one day to another so drastically and we filled it up with youth players that were talented, but far from ready.

"In the end it didn’t work out and we spent loads of money on replacements that were not as good as the players we had let go."

According to Kirchhoff, M'Vila stayed in contact with several players at Sunderland and was desperate to return to Wearside.

Yet the Black Cats failed sign the popular midfielder, leaving the squad light in the middle of the park.

"What I know is he what literally at the airport on the day," added Kirchhoff. "He spoke to the club a lot and remained in contact with Younes, Wahbi and Lamine throughout the entire time. He was desperate to come back because, like me, he had such a great time.

"You sometimes underestimate players like DeAndre Yedlin, too. From an outside perspective £4.5million might seem too much for players like him, but he was important. The same with Younes (Kaboul) and we let him go so cheap. You can’t explain this.

"It got to a point where John [O’Shea] was number one choice again and, nothing bad against John, but he was happy to be back up and we had a central defenders that had done so well just broken up.

"The dressing room losing these players changed the atmosphere too and... it just wasn’t good.