In 200 NHL games, all with the Sharks, Hertl has 102 points (49 goals, 53 assists).
Gudas, 26, had 14 points and an NHL career-high five goals in 76 games last season. He was second in the League with 304 hits, and second on the Flyers with 157 blocked shots.
In 202 NHL games with the Tampa Bay Lightning and Flyers, Gudas has 46 points (12 goals, 34 assists).
Former Washington Capitals defenseman Tomas Kundratek will take Gudas' place on Team Czech Republic. The 26-year-old had 24 points for Riga Dynamo and Slovan Bratislava of the Kontinental Hockey League last season. In 30 games with the Capitals from 2011-13, he had a goal and seven points.
Forward Michal Birner will replace Hertl. The 30-year-old had 13 goals and 39 points in 51 games for Bili Tygri Liberec in the Czech Extraliga last season before signing with Traktor Chelyabinsk of the KHL.
"Birner is a universal, fast-skating forward who can play in all positions. And Kundratek is a mobile defenseman, not as tough as Gudas, but proven on the international stage," coach Josef Jandac said.
The loss of Hertl, Krejci and Gudas could be critical for Team Czech Republic. General manager Martin Rucinsky said he reached out to Dallas Stars forward Jiri Hudler about joining the team, but he declined.
"We wanted to have him, I tried to get in touch with him for two days with no reaction. His agent said that [he] wanted to get ready for the NHL season and that he doesn't want to go [to the World Cup]," Rucinsky said. "I respect that, I have nothing against Jiri and I wish him good luck in the season."
Team Czech Republic opens training camp at O2 Arena in Prague on Monday. The World Cup will be played at Air Canada Centre in Toronto from Sept. 17 to Oct. 1.
TEAM CZECH REPUBLIC ROSTER
G Petr Mrazek, Detroit Red Wings
G Michal Neuvirth, Philadelphia Flyers
G Ondrej Pavelec, Winnipeg Jets
D Michal Jordan, UFA
D Michal Kempny, Chicago Blackhawks
D Tomas Kundratek, Slovan Bratislava (KHL) \
D Zybnek Michalek, Arizona Coyotes
D Jakub Nakladal, Calgary Flames
D Roman Polak, Toronto Maple Leafs
D Andrej Sustr, Tampa Bay Lightning
F Michal Birner, Traktor Chelyabinsk (KHL) \
F Roman Cervenka, Fribourg-Gotteron (Swiss NLA)
F Radek Faksa, Dallas Stars
F Michael Frolik, Calgary Flames
F Martin Hanzal, Arizona Coyotes
F Ales Hemsky, Dallas Stars
F Dmitrij Jaskin, St. Louis Blues
F Milan Michalek, Toronto Maple Leafs
F Ondrej Palat, Tampa Bay Lightning
F David Pastrnak, Boston Bruins
F Tomas Plekanec, Montreal Canadiens
F Vladimir Sobotka, Avangard Omsk (KHL)
F Jakub Voracek, Philadelphia Flyers
* - named to roster today