Eight current squad members have been involved with their national teams in North America, with Maxim De Cuyper the last to suffer elimination.
Luka Vuskovic, who is widely expected to join from Spurs, has also been at the tournament, with Croatia.
Jason Steele continues to train with England as they go into the final week of the tournament.
Hurzeler is not worried that so many players will join up with pre-season already under way.
The Albion head coach said: “We have a few national players that have now a few days off after the World Cup.
“They come back with different experiences. Some are really excited, some are quite disappointed, so they need their time off.
“We work here with the rest and we add some loan players and under-21 players.
“It's still good to work with them, but we still miss quite a few players.
“With new signings, we're about nine players at the moment that are not with us.”
Albion do not kick-off competitive action for another five weeks but clubs across the Prem will be waiting on World Cup players.
Hurzeler told TalkSPORT: “Everyone has the challenge, that’s the first thing.
“The most important is that the players come back with a fresh mind.
“And the third thing is that I'm quite convinced that we have built a strong foundation in the last months and, when they come back, it's just about repetition, just about emphasising the same things and get them back on track.
“So I think these three things make it quite easy to handle, and I see it more as opportunities for the guys who are not involved in the tournament, to give them game time, to give them minutes as much as possible, and they have a chance to get closer to the guys who are playing.”