Career
He also represents the German national basketball team in the international competitions. Standing at 2.08 m (6 ft 10 in), he plays at the center position. Zirbes first played soccer, but opted to focus on basketball when he was 12 years old.
He started his basketball career in the youth set up of TBB Trier before signing his first professional contract with TBB at the age of 17.
In the 2008-2009 campaign, Zirbes was named Most Valuable Player of the German youth league NBBL.
He played with TBB Trier until signing a three-year contract with Brose Baskets in June 2012. On August 5, 2014, Zirbes signed a two-year deal with the Serbian team Crvena zvezda.
In June 2015, he exercised his player option for the 2015-2016 season. He represented the German Junior National Teams at the 2008 U18 European Championships and the 2010 U20 European Championships and was handed his first cap for the German Men"s National Team in August 2009, when Germany took on the Netherlands.