Mamour Ndiaye has joined Saint-Étienne from Sarpsborg 08, signing a contract until 2030 for a transfer fee of 1.5 million euros, plus bonuses. Ndiaye will compete with Gauthier Larsonneur for the starting goalkeeper position. Ndiaye stated that ASSE is a historic club that everyone hopes to know in their career and that he is eager to begin playing for the team. He added that his adaptation will be facilitated by his command of French, and that he wants to meet all the supporters of the club. Ndiaye also said he is ready to do everything to represent the club.

Mamour Ndiaye was expected to become AS Saint-Étienne's third summer signing after an agreement of approximately one million euros had been reached with Sarpsborg 08. According to Peuple-Vert, the player traveled to L'Étrat to finalize his transfer. However, a disagreement over contract terms between Ndiaye, his representatives, and ASSE is now jeopardizing the deal. The medical examination was scheduled, but negotiations have stopped progressing.

According to information, an agreement has been reached between AS Saint-Étienne and Sarpsborg 08 for the transfer of Mamour Ndiaye for a fee of 1.5 million euros plus bonuses. The 20-year-old goalkeeper joined Sarpsborg 08 from the Oslo Academy of Dakar in February 2024. Ndiaye is still under contract with the Norwegian club until December 2027. It was previously revealed that AS Saint-Étienne was interested in the player.

The most concrete option for 20-year-old Sarpsborg goalkeeper Mamour Ndiaye is a move to AS Saint-Étienne. The Senegalese U20 international is under contract with the Norwegian club until December 2027 and is seen by Saint-Étienne's management as a way to create genuine competition for current starting goalkeeper Gautier Larsonneur. Ndiaye is reportedly particularly excited by the opportunity to take on this challenge. The French club's officials now need to find the financial means to convince Sarpsborg to sell their player. Ndiaye, who has been capped four times for Senegal's U20 team, joined Sarpsborg in February 2024 and has made 10 appearances in the 2025/2026 Eliteserien season. His current market value is €1.20m, according to Transfermarkt.