Frolík played two seasons in the Czech Extraliga for Rabat Kladno before being selected tenth overall in the 2006 NHL Entry Draft by the Florida Panthers. While playing in Kladno, Frolík was nicknamed "The Baby Jágr" due to his similar playing style and appearance to Jaromír Jágr, who also played for Kladno earlier in his career. To add to his overwhelming resemblance, Frolík, who cites Jágr as his role model, wore #68 at the Panthers' rookie camp.