United States manager Gregg Berhalter has added nine foreign-based players to his preliminary squad list ahead of CONCACAF Nations League matches against Canada and Cuba.

The group is headlined by Chelsea midfielder Christian Pulisic, Wolfsburg defender John Brooks and Ajax defender Sergino Dest who recently committed his international future to the U.S. team. Fortuna Dusseldorf goalkeeper Zack Steffen was originally on the list of additional players, but has been forced to withdraw due to knee tendinitis.

"We are happy to be able to call on this core group of players, especially with the significance of these upcoming matches." Berhalter said. "They have been performing well for their clubs, and we look forward to preparing to get the results we need against Canada and Cuba. As competitors, these are the moments you relish. We will be ready."

With the MLS Cup final set to take place this Sunday, and the overall roster situation remains fluid. A group of 20 MLS players who are now in their offseason has been training in Bradenton, Florida. since Nov. 2 in a bid to get a head start on preparation. Not all of those players will make the roster for the final training camp, which is set to begin on Nov. 10.

Five players who are part of the current camp -- defender Mark McKenzie, midfielders Brenden Aaronson and Djordje Mihailovic, and forwards Jeremy Ebobisse and Jonathan Lewis -- will depart the group later this week to join the U.S. Under-23 team as they continue their preparations for next spring's CONCACAF Olympic Qualifying Championship. The U23s will participate in the United International Football Festival featuring Argentina, Brazil and Chile in the Canary Islands from Nov. 7-17

Players taking part in the MLS Cup final may also be added, though all nine of the foreign-based players will be on the final camp roster.

- CONCACAF Nations League: All you need to know

The return of the oft-injured Brooks provides a significant boost for Berhalter. The World Cup veteran is the most talented defender in the U.S. player pool, but was unavailable last month when the U.S. fell to Canada 2-0 in Toronto due to a groin injury. He has gone the full 90 minutes in each of Wolfsburg's past two league games.

The matches will provide an opportunity for Dest to be officially cap-tied to the U.S. following his announcement last week that he would represent the American side instead of the Netherlands.

Fortuna Dusseldorf midfielder Alfredo Morales is also back in the fold after returning from a groin strain that forced him to miss last month's Nations League matches. The U.S. has been looking for increased bite in midfield and Morales' combative style could help the team in that regard.

FULL USMNT ROSTER BY POSITION (Club; Caps/Goals)

GOALKEEPERS (3): Brad Guzan (Atlanta United FC; 62/0), Sean Johnson (New York City FC; 8/0), Matt Turner (New England Revolution; 0/0)

DEFENDERS (10): John Brooks (Wolfsburg/GER; 37/3), Reggie Cannon (FC Dallas; 9/0), Sergiño Dest (Ajax/NED; 2/0), Chase Gasper (Minnesota United FC; 0/0), Nick Lima (San Jose Earthquakes; 9/0), Aaron Long (New York Red Bulls; 14/2), Daniel Lovitz (Montreal Impact/CAN; 12/0),Tim Ream (Fulham/ENG; 38/1), DeAndre Yedlin (Newcastle United/ENG; 60/0), Walker Zimmerman (LAFC; 11/2)

MIDFIELDERS (5): Sebastian Lletget (LA Galaxy; 12/2), Weston McKennie (Schalke/GER; 17/6), Alfredo Morales (Fortuna Düsseldorf/GER; 14/0), Wil Trapp (Columbus Crew SC; 20/0), Jackson Yueill (San Jose Earthquakes; 4/0)

FORWARDS (6): Paul Arriola (D.C. United; 30/5), Corey Baird (Real Salt Lake; 4/0), Tyler Boyd (Besiktas/TUR; 8/2),Christian Pulisic (Chelsea/ENG; 34/14), Josh Sargent (Werder Bremen/GER; 11/3), Gyasi Zardes (Columbus Crew SC; 54/10)