The gifted midfielder has amassed 179 games since debuting for the Roar in 2010, but confirmed the A-League club couldn't guarantee him a new contract.
Broich's best achievements at Brisbane Roar
3 A-League Championships (2010/11, 2011/12, 2013/14)
Broich played a major role in all of the Roar's championship wins, particularly in the 2014 grand final against Western Sydney Wanderers.
The German helped Brisbane come from behind to claim a dramatic win over Tony Popovic's men in extra-time and he was duly awarded the Joe Marston Medal, alongside Iacopo La Rocca.
2 Premiers' Plates (2010/11, 2013/14)
The former Borussia Monchengladbach midfielder was at the centre of the Roar's record 36-match unbeaten streak under now Socceroos coach Ange Postecoglou.
It remains an Australian sporting record, commencing in the 2010/11 season, with Brisbane taking out the premiership-championship double.
Two-time Johnny Warren Medallist (2011/12, 2013/14)
Broich took out the A-League player of the season twice in the space of three seasons.
Off the back of some incredible form, Broich's brilliance culminated in a man-of-the-match performance in the 2014 grand final.
2014 Joe Marston Medal for best on field in grand final (shared with Wanderers' Iacopo La Rocca)
The German was influential throughout the contest and played a hand in both Brisbane goals as they came from behind to defeat Western Sydney Wanderers.
Broich shared the man of the match, Joe Martson Medal honours, with former Wanderers hard man Iacopo La Rocca.