Sunderland's signing of Dennis Cirkin from Tottenham Hotspur has proven to be a fantastic investment, as the 21-year-old has established himself as a big part of Tony Mowbray's side at the tender age of 21.

How has Cirkin done since signing for Sunderland?

Under ex-manager Lee Johnson, the Black Cats would sign the young defender from Spurs in the summer of 2021 for an undisclosed fee, with the then-teenager quickly establishing himself as a regular for Sunderland in League One.

He would make 37 appearances in the third tier last season as the north east side were promoted from the third tier via the playoffs, and he has continued as a regular under both Alex Neil and Mowbray so far this campaign.

In 27 Championship appearances, the versatile defender has contributed an impressive five goals and one assist, which included an eye-catching brace in the 2-1 win over West Brom recently, which kept the Black Cats in with a chance of securing a playoff spot again this month.

Mowbray was full of praise for the 21-year-old machine following the game, saying:

"Dennis is an aggressive, powerful guy and you just have to keep pushing him to believe in himself. He's undoubtedly got Premier League qualities, he's a powerful unit who can nick goals for you.

"Why he's in the box, I'm not really sure. I did ask my coaching staff, 'why on earth is the guy on the left of my back three in the box?' I think that's credit to the bravery of the team, he plays it forward and just keeps it going."

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Cirkin's impressive performances at such a young age have seen him attract interest from former side Spurs in recent times but he may have aspirations of reaching the Premier League with the Black Cats, given that he was never afforded the same opportunities with the north London side.

If he were to leave the Stadium of Light in the summer, Sunderland would be sure to earn a significant fee for him, as his transfer value has rocketed during his time at the club.

How much is Dennis Cirkin worth now?

In the summer of 2022, Transfermarkt valued the English defender at just €1.2m (£1.06m) but that valuation has shot up to €2.2m (£1.93m) in less than a year, which represents a phenomenal 83% increase.

Should Sunderland push on again next season, or even achieve promotion through the playoffs this year, then Cirkin's transfer value will surely increase further.

At just 21, the left-back has a huge amount of potential, and Sunderland deserve a lot of credit for putting their faith in a teenager with no experience in senior football, as they are now reaping the benefits.