German media reported that Borna Sosa rejected several offers to return to the Bundesliga on loan this summer.

Croatian international Borna Sosa, 27, is a player of significant interest to 1. FSV Mainz 05. Mainz is hoping to persuade both Sosa and Crystal Palace to agree to a loan deal. The club believes Sosa's precise passes and excellent crosses would be beneficial to the team. It is not known if Crystal Palace is willing to loan out the former Ajax left-back. Sosa has made 27 appearances for Croatia, scoring 2 goals. In the current 2025/2026 Premier League season, he has played in 3 matches. His market value is estimated by Transfermarkt to be €4.00m.