Stefan Thesker (born 11 April 1991) is a German professional footballer who plays as a centre back for Austrian club SKN St.

[1] Born in Ahaus, Germany, Thesker played for TuS Wüllen and Schalke 04 youth teams before moving to Netherlands, joining Twente in 2005 and subsequently signed his first professional contract four years later.

[2] After featured for the Jong FC Twente, Thesker was loaned out to Fortuna Sittard for the rest of the season in the January transfer window.

[10] After returning from injury, he finally made his TSG 1899 Hoffenehim debut on 9 March 2013 against Greuther Fürth, coming on as a second-half substitute, in a 1–0 win.

[19] On 30 April 2014, it was announced Thesker had signed a pre-contract agreement with Hannover 96 and would join them on 1 July 2014 on a free transfer after rejecting a new contract at 1899 Hoffenheim.

[21] However, in the club's pre-season tour, he suffered a thigh injury but soon managed to recover just in time for the start of the season.

However, ahead of the 2015–16 season, Thesker found himself out of the first team and was placed on the substitute bench after Benedikt Röcker was preferred instead.

[32] Three days after signing for the club, on 31 January 2016, he made his Twente debut, playing 60 minutes, in a 3–1 win over Utrecht.

[33] After being sidelined for two months, due to his diagnosis with cancer,[34] he made his return for the reserve side, in a 0–0 draw against Brabant United U21 on 15 March 2016.

[35] Five days after returning to playing, Thesker scored his first two goals in a 2–2 draw against AZ Alkmaar, having come on as a second-half substitute.

In December 2015, Thesker found himself in a controversy when he was captured on video by Nuremberg fan, scolding a bouncer several times and mocking his salary.

[citation needed] In February 2016, Thesker announced that he diagnosed with testicular cancer and had to have a tumor removed at the surgery.