Team Czech Republic general manager Martin Rucinsky said Jagr had declined a roster spot after a week of deliberation.
"We spoke to each other during the weekend and his final decision was he wouldn't be going," Rucinsky told Denik Sport. "It would be too difficult for him to get ready for such an important tournament during the summer. And he said at last year's [IIHF] World Championship that he was done with the national team. He also will have a lot of work with Kladno [Czech league team Jagr owns]. He wants to do some work with the team and therefore wouldn't be able to get ready for the World Cup in time."
Team Czech Republic coach Josef Jandac said he is considering adding up to three players from the Czech Republic roster from the 2016 IIHF World Championship.
Here is NHL.com's projection of the final seven players on the roster:
THE FINAL 7
F: Radek Faksa (Dallas Stars), Tomas Fleischmann (Chicago Blackhawks), Ales Hemsky (Dallas Stars), Milan Michalek (Toronto Maple Leafs)
D:Tomas Kundratek (Slovan Bratislava, KHL), Zbynek Michalek (Arizona Coyotes), Michal Jordan (Carolina Hurricanes)
Milan Michalek is a proven workhorse on the international stage, and Faksa and Hemsky found some chemistry in Dallas during the Stanley Cup Playoffs.
Assuming Team Czech Republic won't have forward David Krejci (Boston Bruins), who is expected to need five months to recover from hip surgery April 25, they would have to add another creative player who can play center. Jiri Hudler of the Panthers could be an option, but the coaches still have time to add his name later should they scratch Krejci for medical reasons.
The other big question is whether 39-year-old defenseman Marek Zidlicky (New York Islanders) will be playing next season. Team Czech Republic needs a player with his skill set because they have no other offensive-minded defender with his abilities and experience. It is possible Zidlicky will retire during the summer, which would open spots for Kundratek and Jordan.
Potential lineup
Forwards
Jakub Voracek - Tomas Plekanec - Michael Frolik
Ondrej Palat - Jiri Hudler - David Pastrnak
Tomas Hertl - Radek Faksa - Ales Hemsky
Milan Michalek - Martin Hanzal - Tomas Fleischmann
Vladimir Sobotka
Defensemen
Andrej Sustr - Radko Gudas
Roman Polak - Zbynek Michalek
Michal Kempny - Tomas Kundratek
Michal Jordan
Goaltenders
Petr Mrazek
Ondrej Pavelec
Michal Neuvirth
