He is on the books of BSG Chemie Leipzig and wears shirt number 17. His main role on the pitch is Forward. His stronger foot is Right. His estimated market valuation currently stands at 100K €.

His latest transfer saw him join BSG Chemie Leipzig from Carl Zeiss Jena via on 2026-01-25.

During the German Regionalliga 2025-2026 campaign, Kay Seidemann made 15 appearances, scoring 2 goals and adding 0 assists. He averaged 0.1 goals per match from 0 shots, with 0 on target.