The son of former professional basketball player Marc Suhr, a 7-foot center who won four caps for the German men's national team during his career, Kratzer started out with
BBC Bayreuth’s youth team at age 12, moving on to the
Brose Bamberg youth program in 2012. Representing Bamberg's development squad
Baunach Young Pikes, he made his debut in Germany's third-tier
ProB during the 2013-14 season, helping the team win promotion to
ProA that year. Kratzer made his first appearances in Germany's top-flight
Basketball Bundesliga for Bamberg in the 2016-17 campaign, while still being a regular in the reserve team. Averaging 14.6 points, 12.7 rebounds and 1.5 blocks a game for Baunach in 2016-17, he garnered
ProA Player of the Year honors. Looking to take the next step in his career and to gain more playing time in the Bundesliga, he signed on loan for
s.Oliver Würzburg in June 2017. On 20 November 2018 he signed with
Skyliners Frankfurt of the
Basketball Bundesliga. On 31 July 2020 he signed with
Telekom Baskets Bonn of the
Basketball Bundesliga (BBL). In 2023 Kratzer won the Basketball Champions League with Bonn, remaining scoreless in the final against Hapoel Jerusalem, but contributing a team-high six rebounds. On 8 July 2023 he signed with
Paris Basketball of the
LNB Pro A (BBL). == International career ==