Originally a product of the HC Sareza Ostrava team, Rostislav Olesz made his debut in the senior Extraleague as a 15-year-old in 2000-2001. A key member of the junior national team of the 1985 borns. he played at the 2003 Under-18 WJC just like on the 2004 Under-20 WJC. Broke into the Czech senior national team at the Baltika Cup in 2003.
Olesz was drafted by the Florida Panthers in the first round, 7th overall, of the 2004 NHL Draft.
A player without any glaring weakness, Olesz is a character guy who gives everything to the team's success. He is offensively talented, well-balanced and always showing a nasty edge in his play. Olesz plays a combative style and is a good hitter. He is a valuable asset to both powerplay and penalty killing units. A solid skater with a decent agility, Olesz impresses with his excellent lower-body strength. He has a sharp hockey sense and vision. Also very good in the faceoff circle, Olesz emerges as both a smart passer and a strong finisher. He possesses a good variety of shots, he could only fire the puck more often. Olesz impresses with his strong defensive awareness, he limits the opposing players' options effectively. A mature player, he doesn't tend to take shifts off.
Olesz was dealt to the Chicago Blackhawks in the 2011 deal that sent Brian Campbell to the Florida Panthers.