[7] On 24 January 2017, Zirbes returned to Germany and signed with Bayern Munich on loan, till the end of the season.

[10][11] During his one-year stint with KK Crvena zvezda, Zirbes averaged 7.7 points and 4 rebounds in just over 15 minutes per game.

His best game was on 8 October 2018 in a 87–71 win against KK Budućnost in the round 2 of the ABA League regular season, where he scored 19 points and grabbed 6 rebounds in 22 minutes.

[13] On 12 July 2020, Zirbes signed with Shabab Al Ahli of the UAE National Basketball League.

[20] He was handed his first cap with the senior German national basketball team in August 2009, when Germany took on the Netherlands.