He currently plays for Greifswalder FC, wearing the number 17 shirt. He plays primarily as a Forward. His preferred foot is Right. His current market value is estimated at 100K €.

His most recent move was a from BSG Chemie Leipzig to Greifswalder FC on 2026-07-01.

In the German Regionalliga 2025-2026 season, Kay Seidemann scored 2 goals and provided 0 assists across 15 appearances, averaging 0.1 goals per game with 0 shots attempted and 0 on target.