Career
In the 2001 National Hockey League Entry, he was drafted 253rd overall, in the 7th round by the Saint Louis Blues. He was then signed to an National Hockey League contract. Petr Čajánek played for The Human Context Zlín from 1993 to 2002.
In the 2001-2002 season, he was the leading scorer in the Czechoslovakian Extraliga.
On February 26, 2007, Čajánek was placed on waivers by the Saint Louis Blues, which would have effectively allowed any other National Hockey League club to sign him. When no other National Hockey League teams tendered Čajánek an offer, the Blues re-signed him to a league-minimum contract, and added him back to their roster.
Though he was placed on waivers, the 2006-2007 season was his best, putting up a career high 48 points, good for 3rd on the Blues. On October 21, 2007, Čajánek signed a 1-year, $900,000 deal to play for Ak Bars Kazan in the Russian Super League for the rest of the season.