Forward Folarin Balogun will miss the Concacaf Gold Cup because of an ankle injury and was among three players dropped Sunday from a United States roster already without Christian Pulisic, Weston McKennie, Timothy Weah, Antonee Robinson, Yunus Musah and Giovanni Reyna.
Defender DeJuan Jones (lower body) and midfielder Sean Zawadzki (knee) were also dropped by coach Mauricio Pochettino, who added defenders Walker Zimmerman and Nathan Harriel along with forward Paxten Aaronson.
Balogun struggled through an injury hit season with Monaco, returning to competition in March after undergoing surgery in December on a dislocated shoulder. He had previously been sidelined for about two months and returned to competition at the end of November. But he took a hit during a game against Marseille that aggravated the problem.
Four players have been replaced from the 27-man group announced May 22. Goalkeeper Patrick Schulte injured an oblique and was replaced Wednesday by Chris Brady.
Aaronson, 21, joined 24-year-old brother Brenden on the roster and could play with him on the national team for the first time. Paxten's lone U.S appearance was in a friendly against Colombia in January 2023.
Harriel is among seven players who could make U.S. debuts, joined by Brady, goalkeeper Matt Freese, right back Alex Freeman, midfielder Sebastian Berhalter, midfielder/winger Quinn Sullivan and forward Damion Downs.
The U.S. is coming off poor performances at last year's Copa América and the Concacaf Nations League in March, and this will be the last extended training camp during a FIFA fixture period until players report ahead of next year's World Cup.
Players started arriving Sunday for training in Chicago. The Americans have friendlies against Turkey on June 7 in East Hartford, Connecticut, and Switzerland three days later in Nashville, Tennessee, then meet Trinidad and Tobago, Saudi Arabia and Haiti in the first round of the Gold Cup.
Full U.S. roster:
Goalkeepers: Chris Brady (Chicago), Matt Freese (New York City), Zack Steffen (Colorado), Matt Turner (Crystal Palace)
Defenders: Max Arfsten (Columbus), Sergiño Dest (PSV Eindhoven), Alex Freeman (Orlando), Mark McKenzie (Toulouse), Tim Ream (Charlotte), Chris Richards (Crystal Palace), Miles Robinson (Cincinnati), Walker Zimmerman (Nashville)
Midfielders: Brenden Aaronson (Leeds), Tyler Adams (Bournemouth), Sebastian Berhalter (Vancouver), Johnny Cardoso (Real Betis), Luca de la Torre (San Diego), Diego Luna (Salt Lake), Jack McGlynn (Houston), Quinn Sullivan (Philadelphia), Malik Tillman (PSV Eindhoven)
Forwards: Paxten Aaronson (Utrecht), Patrick Agyemang (Charlotte), Folarin Balogun (Monaco), Damion Downs (Cologne), Brian White (Vancouver), Haji Wright (Coventry)
Information from The Associated Press was used in this story.