[1] Bartels began his career at TSV Russee and later played for SpVgg Eidertal Molfsee before joining Holstein Kiel in 2002.

[4][5] In his first season he was able to command a regular place in the team from matchday 3 onwards and made 29 league appearances scoring four goals.

[11] On 1 March 2019, following a long time out of action with complications during the healing process, it was announced he would play in two matches for the club's reserves before he would return to the first team squad.

[14] He missed the rest of the season due to a muscle injury with manager Florian Kohfeldt expecting him to return in time for pre-season preparation in the summer.

[16] On 13 January 2021, he scored a goal and the winning penalty for Holstein Kiel as they knocked out defending champions Bayern Munich in the DFB-Pokal.