On 21 August 2014 Knudsen was farmed to affiliated club Prato in a temporary deal.
[2] The club signed several players from Inter as part of the partnership agreement.
[3][4] On 15 September 2017, Knudsen signed an amateur contract with Norwegian club Sarpsborg 08.
[8] After three seasons in Germany, it was confirmed on 26 August 2024 that Knudsen had signed with the recently relegated Danish 1st Division club Hvidovre IF.
[9] Knudsen made his competitive debut for Denmark youth team on 12 October 2011, a 4–1 win against Italy U17.