Nguyen, whose New England Revolution advanced to the Eastern Conference finals of the MLS Cup Playoffs this weekend, has not been called up by the U.S. since 2007.
The U.S. will play Colombia on Friday, Nov. 14 in London at Craven Cottage -- the home stadium of Fulham FC -- before meeting Ireland on Tuesday, Nov. 18 in Dublin.
The roster includes a mix of players based in Europe and North America, including multiple players who are still competing with their clubs for the MLS Cup. Of the 12 players on the roster based in the United States, two are non-MLS players: Miguel Ibarra (Minnesota United FC) and Jordan Morris (Stanford University). Ibarra received his first cap against Honduras in October.
A total of 16 players on the list played with the U.S. at this summer's World Cup in Brazil, including eight of nine players listed as defenders on the roster. Klinsmann elected to include six forwards, six midfielders and four goalkeepers.
Notable omissions from the roster include forward Clint Dempsey and midfielder Michael Bradley, who is recovering from foot surgery.
In October, the U.S. drew 1-1 in friendlies with Ecuador and Honduras.
The complete roster is below:
Goalkeepers: Brad Guzan (Aston Villa), Bill Hamid (D.C. United), Sean Johnson (Chicago Fire), Nick Rimando (Real Salt Lake)
Defenders: DaMarcus Beasley (Houston Dynamo), Matt Besler (Sporting Kansas City), John Brooks (Hertha Berlin), Geoff Cameron (Stoke City), Timmy Chandler (Eintracht Frankfurt), Greg Garza (Club Tijuana), Fabian Johnson (Borussia Monchengladbach), Jermaine Jones (New England Revolution), DeAndre Yedlin (Seattle Sounders FC)
Midfielders: Kyle Beckerman (Real Salt Lake), Alejandro Bedoya (Nantes), Mix Diskerud (Rosenborg), Julian Green (Hamburg), Alfredo Morales (Ingolstadt), Lee Nguyen (New England Revolution)
Forwards: Jozy Altidore (Sunderland), Miguel Ibarra (Minnesota United FC), Jordan Morris (Stanford), Rubio Rubin (Utrecht), Bobby Wood (1860 Munich), Chris Wondolowski (San Jose Earthquakes)
- Stanley Kay