The 17-year-old had four goals and four assists in 38 games for Liberec in the Czech pro league this past season. Zacha had three goals and two assists in seven games at the world men's under-18 championship in April when the Czech Republic took the silver medal.
But Zacha's agent, Allan Walsh, said on Twitter that Zacha is under contract to a professional team in his home country and is not interested to playing in the OHL.
"Sarnia just wasted the #1 overall pick in the CHL Import Draft on a player who's not coming and has a professional contract. #RookieGM," Walsh posted on Twitter.
Zacha, a six-foot-two, 200-pound forward, is eligible for the 2015 NHL entry draft.
The Sherbrooke Phoenix selected Russian left-winger Vladislav Kamenev with the second pick and the Lethbridge Hurricanes drafted Russian winger Nikita Milekhin at No. 3. Kamenev was taken in the second round of the NHL draft last week by the Nashville Predators.
The 60 teams in the CHL, which includes the Western, Ontario and Quebec major junior men's hockey leagues, each get two selections in the import draft. Each team is eligible to dress two imports each season.
But this year's import draft marked the first time teams were not allowed to select goaltenders.
“In partnership with Hockey Canada, the CHL has identified the need to further develop Canadian goaltenders by providing increased opportunities for them to compete in our league and succeed at the next level," CHL commissioner David Branch said in a statement when that decision was made.
Import goaltenders drafted prior to this year are allowed to continue to play in the CHL until they've exhausted their major junior eligibility.