Career
Kreer began his career playing for the youth side of BSG Lokomotive Delitzsch and then 1. Football Club Lokomotive Leipzig. After being promoted to the Leipzig senior squad, Kreer played 241 games in the Deutsche Demokratische Republik-Oberliga for the club, scoring 10 goals.
Kreer played for the East Germany team at the 1980 Under-21 European Championships, and was sent off as the team were beaten 1–0 by the Union of the Soviet Socialist Republics in the second final in Moskva.
He made his full international debut for East Germany on 22 September 1982 in a 2–2 draw against Bulgaria in Burgas. Kreer played a total of 65 times for East Germany (making him the 10th most-capped player).
He also scored two goals in his international career, which ended in 1989. In 1991-1992, Kreer played a season in the 2.
After ending his playing career, he worked with the German Football Association training young talent around Leipzig.