[4] In the 2013–14 season he made his Superliga breakthrough, as defender Lasse Nielsen left for the Dutch team NEC Nijmegen, thus leaving a spot open in the centre of defense.

On 26 July 2017, Thelander was the fifth footballer (after Michael Essien, Stathis Tavlaridis, Jens Wemmer and Niklas Hult) in eight months to file an appeal against Panathinaikos for payments' delay.

[15] On 26 July, he made his first appearance for Vitesse, starting in the first leg of their UEFA Europa League qualification round against Viitorul Constanța.

[22] On the same day that he had his contract with AaB terminated, 1 September 2024, it was confirmed that Thelander had signed with fellow Danish Superliga club Silkeborg until the end of the year.

[24] After having made nine appearances in the league and three in the Danish Cup, on 18 December, Silkeborg announced that Thelander's contract would not be extended and he would be released by the club.

[25] On 3 February 2025, on transfer deadline day, Danish Superliga side Lyngby announced the signing of Thelander on a deal until June 2026.