The transfer of Marcin Flis to Wisła Płock was announced by the club ahead of the 2026/2027 Ekstraklasa season. Flis joined on a free transfer, with his contract valid until 30 June 2028.

According to Nafciarski.pl, Marcin Flis, a Polish defender from Pogoń Siedlce, will be presented as a new signing for Wisła Płock. Wisła is expected to announce the 32-year-old's arrival this week. The player will join on a free transfer after his contract with Pogoń expires. Wisła's acting president, Maciej Wiącek, previously referred to this move as a 'mysterious transfer' during a press conference on Tuesday. The transfer will reunite Flis with the new coach, Adam Majewski. Flis previously played under Majewski at Stal Mielec. Flis will be the club's third new player. The length of his contract is set to be revealed in the official statement. The former Poland U20 international has one cap for the side and scored 10 goals and provided one assist in 29 appearances in the Betclic 1 Liga during the 2025/2026 season. Transfermarkt lists his current market value as €100k.