Dusseldorf, Germany - When the US men's national soccer team gathers next week for its final two warm-ups ahead of this fall's World Cup, four athletes who were expected to have key roles won't be there.

Missing from the 26-man roster coach Gregg Berhalter summoned Wednesday are defenders Antonee Robinson and Miles Robinson, goalkeeper Zack Steffen, and forward Tim Weah. All are unavailable because of injury.

The US will face Japan on September 23 in Dusseldorf, Germany, and Saudi Arabia on September 27 in Murcia, Spain. Both opponents will also play in the World Cup. The US opens that tournament against Wales on November 21.

"As we approach the World Cup, this is another opportunity for us to take a step forward as a group," Berhalter said in a statement.

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"We have a strong roster and can use these games as a measuring stick against World Cup opponents as we continue to gain valuable experience ahead of going to Qatar."

But Berhalter will be doing that in this international window without four players who were figured to compete for starting spots.

Steffen, who left Manchester City for Middlesbrough of the second-tier English Championship in order to get more playing time ahead of the World Cup, hasn't played since August 20 because of a knee injury.

Antonee Robinson, who went the full 90 minutes in Fulham's first five games, came out of the team's September 3 match after 28 minutes with an ankle injury and hasn't played since. Miles Robinson sustained an Achilles injury in May and is out of the World Cup. Weah is sidelined with a foot injury.

Berhalter did get some players back, with forwards Ricardo Pepi and Gio Reyna returning to the national team for the first time since the March qualifiers. Defenders Sergiño Dest and Chris Richards were last with the squad during the January/February qualifying window.

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Reyna is coming off a week in which he became the first US international to record two assists in a UEFA Champions League match, helping Borussia Dortmund to a 3-0 victory over FC Kobenhavn.

The US roster's average age will be 24 years, 201 days as of the first day of training September 19; 13 players are 23 or younger.

The 26 players are from teams in nine countries, with MLS contributing the most with eight players.

- Goalkeepers: Ethan Horvath (Luton Town), Sean Johnson (New York City FC), Matt Turner (Arsenal)

- Defenders: Reggie Cannon (Boavista), Cameron Carter-Vickers (Celtic), Sergiño Dest (AC Milan), Aaron Long (New York Red Bulls), Chris Richards (Crystal Palace), Joe Scally (Borussia Mönchengladbach), Sam Vines (Royal Antwerp), DeAndre Yedlin (Inter Miami), Walker Zimmerman (Nashville SC)

- Midfielders: Kellyn Acosta (LAFC), Tyler Adams (Leeds United), Luca de la Torre (Celta Vigo), Weston McKennie (Juventus), Yunus Musah (Valencia), Malik Tillman (Rangers)

- Forwards: Brenden Aaronson (Leeds United), Paul Arriola (FC Dallas), Jesús Ferreira (FC Dallas), Jordan Morris (Seattle Sounders), Ricardo Pepi (Groningen), Christian Pulisic (Chelsea), Gio Reyna (Borussia Dortmund), Josh Sargent (Norwich City)

The 2022 World Cup is set to take place in Qatar from November 20 to December 18.