Defender Geoff Cameron, midfielder Kyle Beckerman and forward Chris Wondolowski will miss the United States' World Cup qualifiers against Mexico and Costa Rica because of injuries, and Tim Howard has regained the No. 1 goalkeeper's job.
Howard, now 37, took a year off from the national team following the World Cup, then late in 2015 and alternated with Brad Guzan.
Guzan started at this year's Copa America and while Howard has been a regular since leaving Everton to join Major League Soccer's Colorado team this summer, the 32-year-old Guzan has not appeared with Middlesbrough in England's Premier League since Aug. 28.
"He thought he would be No. 1 there. He is not," Klinsmann said during Facebook Live interview, adding that Howard "is back to No. 1."
Cameron was paired with John Brooks in central defense during this year's Copa America but has missed Stoke's last two Premier League games after hyperextending a knee against Hull on Oct. 22.
"It's just not healing in time. It's a bummer," said Klinsmann, who was considering moving Cameron into a defensive midfield role.
Omar Gonzalez, Matt Besler, Steve Birnbaum and Michael Orozco are the candidates to replace Cameron at central defender.
Beckerman and Wondolowski play for Major League Soccer teams whose seasons are over, and the nature of their injuries was not clear. Klinsmann went to Colorado on Sunday to personally watch Jermaine Jones and selected the 35-year-old Rapids midfielder, who was sidelined from July 4 until Oct. 23 because of a knee injury.
"Other teams simply fear him," Klinsmann said.
Twenty-six players will be at a training camp ahead of Friday's game against Mexico in Columbus, Ohio, the Americans' opener in the 10-match final round of qualifying in the North and Central American and Caribbean region. Among them is 18-year-old defender Cameron-Carter Vickers, who could make his U.S. debut. He played his first game for Tottenham in the League Cup on Sept. 21.
"He's a very, very promising young player," Klinsmann said.
Also on the roster are 18-year-old Borussia Dortmund midfielder Christian Pulisic; 20-year-old Sunderland midfielder Lynden Gooch, who made his national team debut in an exhibition against New Zealand last month; a 21-year-old Bayern Munich midfielder Julian Green, who has been limited to just two club appearances this season, both in the German Cup.
Forward Aron Johannsson returns for the first time since September 2015. He injured a groin that Sept. 26 playing for Werder Bremen and did not return until Aug. 26.
"Things are not going well there at all, so he's a bit in and out," Klinsmann said. "But he's healthy. He's fit. So he's always bringing a different element to the table."
Portland midfielder Darlington Nagbe was omitted because he is "simply just behind other guys," according to Klinsmann, citing Pulisic, Gooch and 31-year-old Sacha Kljestan, who in September played his first international match after a two-year absence.
The U.S. has beaten Mexico 2-0 in four consecutive home qualifiers, all in Columbus, where the Americans are 8-0-3. After playing El Tri, the U.S. is at Costa Rica on Nov. 15.
Twenty-three players can dress for each game. The top three nations qualify for the 2018 World Cup, and the No. 4 team advances to a playoff against the fifth-place Asian team for another berth.
Goalkeepers: Brad Guzan (Middlesbrough, England), Ethan Horvath (Molde, Norway), Tim Howard (Colorado), William Yarbrough (Leon, Mexico)
Defenders: Matt Besler (Kansas City), Steve Birnbaum (D.C. United), John Brooks (Hertha Berlin, Germany), Cameron Carter-Vickers (Tottenham, England), Timmy Chandler (Eintracht Frankfurt, Germany), Omar Gonzalez (Pachuca, Mexico), Fabian Johnson (Borussia Moenchengladbach, Germany), Michael Orozco (Tijuana, Mexico), DeAndre Yedlin (Newcastle, England)
Midfielders: Alejandro Bedoya (Philadelphia), Michael Bradley (Toronto), Lynden Gooch (Sunderland, England), Julian Green (Bayern Munich, Germany), Jermaine Jones (Colorado), Sacha Kljestan (New York), Christian Pulisic (Borussia, Germany), Caleb Stanko (Vaduz, Liechtenstein), Graham Zusi (Kansas City)
Forwards: Jozy Altidore (Toronto), Aron Johannsson (Werder Bremen, Germany), Jordan Morris (Seattle), Bobby Wood (Hamburg, Germany)