United States forward Gio Reyna was the notable omission as Gregg Berhalter named his first squad since being reappointed as US coach on Wednesday.
Borussia Dortmund forward Reyna has not played since injuring his calf during the CONCACAF Nations League in June but is reportedly back in training with the Bundesliga giants.
Reyna and Berhalter were embroiled in an acrimonious bust-up during last year's World Cup in Qatar that led to Berhalter's future as US national team coach being thrown into doubt.
But the coach said his absence was simply down to his injury and fitness situation.
"Unfortunately, he was ruled out for this camp, but I look forward to continuing to monitor his progress at Dortmund and hopefully getting him back into camp in October," he said.
Berhalter, who led the team to the last 16 in Qatar, did not have his contract extended amid a bitter public row with Reyna and his parents.
Part of the feud included the revealing by Reyna's mother of a physical altercation in 1991 between Berhalter and his then girlfriend, now wife, which prompted a US Soccer investigation.
The probe subsequently found there were no grounds not to reappoint Berhalter, and the coach was re-hired in June.
Berhalter said following his return there was "work to do" in rebuilding his relationship with Reyna, describing him as "an important player to this team."
However Berhalter told Vanity Fair magazine in an interview published on the eve of Wednesday's squad announcement that he had still not spoken to Reyna since their World Cup bust-up.
Asked on a conference call why that conversation had yet to take place, Berhalter suggested there had been some contact with the player.
"He's been responding and for us it's understanding the sensitivity around the issues, understanding the right time, in the right way, and for us, we're committed to every single player in this player pool," he said.
"For us it's about how do we maximize communication with them and target it in a way that we're getting the most out of each and every player. So for this it's just being a little bit more thoughtful, a little bit more sensitive to the past, and I look forward to having conversations with him.
"I look forward to watching his progress and hopefully him getting back on the field, and for us, hopefully being able to include him in the October camp against two good opponents," he added.
Berhalter's squad named on Wednesday face friendlies against Uzbekistan in St. Louis on September 9 before taking on Oman in St. Paul three days later.
One surprise inclusion in the squad was Inter Miami's 18-year-old midfielder Benjamin Cremaschi, who has enjoyed a good run of form playing alongside Lionel Messi.
Miami-born Cremaschi, who has played at youth level for the United States, is also eligible to play for Argentina through his parents.
"We talked to Ben about being able to come into the group and fit into what we're doing, to represent the United States of America, which is a wonderful honor," said Berhalter.
"He grew up here. He's played for youth national team programs in the past and that's where it starts. My conversations with him have been very straightforward. I think he's a very talented player. We're excited about the prospect of bringing him into camp. We're excited to see what he can bring to our team and to our formation because we believe in him and we think he's an excellent player," he said.
Goalkeepers: Drake Callender (Inter Miami), Ethan Horvath (Nottingham Forest/ENG), Matt Turner (Nottingham Forest/ENG)
Defenders: Sergino Dest (PSV Eindhoven/NED), Kristoffer Lund (Palermo/ITA), Mark McKenzie (Genk/BEL), Kevin Paredes (Wolfsburg/GER), Tim Ream (Fulham/ENG), Chris Richards (Crystal Palace/ENG), Antonee Robinson (Fulham/ENG), Miles Robinson (Atlanta United), Joe Scally (Borussia Moenchengladbach/GER)
Midfielders: Johnny Cardoso (Internacional/BRA), Ben Cremaschi (Inter Miami), Luca de la Torre (Celta Vigo/ESP), Weston McKennie (Juventus/ITA), Yunus Musah (AC Milan/ITA), Malik Tillman (PSV Eindhoven/NED)
Forwards: Brenden Aaronson (Union Berlin/GER), Folarin Balogun (Arsenal/ENG), Cade Cowell (San Jose Earthquakes), Ricardo Pepi (PSV Eindhoven/NED), Christian Pulisic (AC Milan/ITA), Tim Weah (Juventus/ITA)