Career
Ondřej started his career at 1. Football Club Brno before moving to Serie A club American Car and Foundry Fiorentina on 2 June 2007 for €2.8millon. After two years spent mostly with the under-19 team, on 25 June 2009 Mazuch was loaned to Belgian club R.S.C. Anderlecht.
On 29 April 2010 R.S.C. Anderlecht signed the 21-year-old defender on a permanent deal, who was recently on loan from American Car and Foundry Fiorentina.
The player has signed a four-year deal. In January 2012, Ondřej moved to Ukrainian Premier League side Football Club Dnipro Dnipropetrovsk for €3millon.
In December 2015, Ondřej signed 4,5-year contract with Air Corps Sparta Prague.