Tom McCoy, BBC Sport journalist:
Sosa will provide security for Tyrick Mitchell at left-back.
He will hope to recapture the form he showed during five seasons at Stuttgart, where he established himself as one of the best attacking full-backs in Germany.
He registered 24 Bundesliga assists during his final three years at the club, the joint-highest figure of any defender during that period, but his career has stalled since then.
Three weeks after joining Ajax in 2023, the man who signed him, director of football Sven Mislintat, was sacked. Sosa soon fell out of favour and started just 10 Eredivisie games before spending 2024-25 on loan at Torino, where he began only 14 Serie A matches.
Though capped at various youth levels by Croatia, he controversially tried to switch allegiance to Germany prior to Euro 2020, only to discover at the last minute it wasn’t permitted under Fifa rules.
He quickly issued a public apology, admitting he had been “wrong” and “naive”, and has since won 26 caps for his native country, including five starts as they reached the World Cup semi-finals in 2022.
With Palace competing in Europe next season, whether it be the Europa League or Conference League, Sosa’s experience could prove a useful option for manager Oliver Glasner.
