"Today the club's board of directors held a meeting at which the decision was taken. It was not Petrzela's initiative," club press attache Andre Tanner said.
Tanner said assistant coach Vladimir Borovichka would take temporary charge of the team.
Zenit has had a disappointing start to the season, and is currently in ninth place in the league with 8 points from six games. It lost 4-1 at home on Sunday in the league to arch-rival Spartak Moscow, and lost 1-0 to CSKA Moscow Wednesday in the first leg of the domestic cup quarterfinals.
Czech coach Petrzela was appointed Zenit's head coach in December 2002. In his first season he led the team to a second-place finish in the Premier League. This season he took the club to the quarterfinals of the UEFA Cup, Europe's second club competition, for the first time in its history, before losing 5-2 on aggregate to Spain's Sevilla.
Tanner refused to speculate on a possible replacement, or to name a date when a new coach would be appointed.
"Talks are probably going on, but no concrete period of time has been set. I can't make any guesses," he said
