Jonathan Klinsmann has been called into camp due to a Zack Steffen injury. (Photo courtesy of the University of California SID)

LONDON – U.S. men’s national team midfielder Darlington Nagbe and goalkeeper Zack Steffen have been forced to withdraw from the upcoming Kickoff Series matches against England and Italy due to injuries suffered during their respective second leg MLS Cup Playoff matches Sunday.

Nagbe was diagnosed with a low-grade hamstring strain following Atlanta United FC’s 3-1 win over New York City FC, while Steffen aggravated a lingering right hamstring issue that began last month following the USA’s match against Colombia.

Hertha Berlin goalkeeper Jonathan Klinsmann was added to the training camp roster, leaving the squad at 27 players ahead of Thursday’s match against England. Having backstopped the USA at the 2017 Under-20 World Cup, Klinsmann will join USMNT camp for the first time when he arrives in London.

The USA faces 2018 World Cup semifinalist England Thursday at Wembley Stadium in London England (3 p.m. ET; ESPN2, UniMas). The USMNT concludes its 2018 schedule against four-time World Cup champions Italy Tuesday at Luminus Arena in Genk, Belgium (2:45 p.m. ET; FS1, UniMas).

U.S. roster (Club; Caps/Goals):

GOALKEEPERS (3):Brad Guzan (Atlanta United FC; 59/0), Ethan Horvath (Club Brugge/BEL; 2/0), Jonathan Klinsmann (Hertha Berlin/GER; 0/0)

DEFENDERS (10):John Brooks (Wolfsburg/GER; 35/3), Reggie Cannon (FC Dallas; 1/0), Cameron Carter-Vickers (Swansea City/WAL; 6/0), Aaron Long (New York Red Bulls; 1/0), Matt Miazga (Nantes/FRA; 10/1),Shaq Moore (Reus Deportiu/ESP; 3/0), Antonee Robinson (Wigan Athletic/ENG; 6/0), Jorge Villafaña (Portland Timbers; 19/0), DeAndre Yedlin (Newcastle United/ENG; 56/0), Walker Zimmerman (LAFC; 3/1)

MIDFIELDERS (12):Kellyn Acosta (Colorado Rapids; 21/2), Tyler Adams (New York Red Bulls; 7/1), Luca de la Torre (Fulham/ENG; 1/0), Marky Delgado (Toronto FC/CAN; 5/0), Romain Gall (Malmö/SWE; 0/0), Julian Green (Greuther Fürth/GER; 14/4), Sebastian Lletget (LA Galaxy; 3/1), Weston McKennie (Schalke/GER; 6/1), Christian Pulisic (Borussia Dortmund/GER; 21/9), Kenny Saief (Anderlecht/BEL; 3/0), Wil Trapp (Columbus Crew SC; 9/0), Tim Weah (Paris Saint-Germain/FRA; 7/1)

FORWARDS (2):Josh Sargent (Werder Bremen/GER; 5/2), Bobby Wood (Hannover 96/GER; 43/13)