When the board of Fredrikstad FK signed a new manager, new coach Tom Nordlie informed Wass that he had no interest in an offensive right defender.

In February, during the three-month winter break in the Superliga between December and March, Wass announced he would not be renewing his contract with Brøndby.

In March 2011, with 14 matches of the season remaining, the attacking force of Wass was recognised, with Coach Henrik Jensen subsequently pushing the player up to right midfielder/winger.

[7] On 15 October 2011, he made his debut, playing in right midfield, making an impact when he provided assist for Yannick Sagbo in a 2–1 loss against Saint-Étienne.

Under new manager Pablo Correa, who succeeded Casoni, Wass secured a place in the first team, mostly being used as left-back, with Sidney Govou taking his former position in right midfield.

[8] On 12 August 2012, in the opening game of the season against Bordeaux, Wass scored a free kick in a match that ended in a 2–3 loss for Evian.

[11][12] He made his debut for the club on 20 August in La Liga, providing an assist to Rodrigo's equaliser in a 1–1 home draw against Atlético Madrid.

[14] Wass was a starter in the 2019 Copa del Rey Final which saw Valencia lift the trophy after a 2–1 victory against Barcelona, his first ever career title.

[15] On 27 November 2019, Wass scored on an overcooked cross from a tight angle, which surprised goalkeeper Kepa Arrizabalaga and allowed Valencia to finish top of their UEFA Champions League group.

[17] He made his competitive debut for the club on 6 February, coming off the bench at half-time for Šime Vrsaljko in a 4–2 loss away against Barcelona at Camp Nou.