US coach Bob Bradley has called 21 players to the National Training Center at The Home Depot Center in Carson, California to prepare for their February 6th friendly against Mexico at Reliant Stadium in Houston.

Sixteen of the players called up are currently on MLS teams, with the other five playing in Denmark and Norway.

Four of the five players left out from the 26-man camp ahead of last week's 2-0 win over Sweden are Jozy Altidore, Maurice Edu, Sacha Kljestan and Marvell Wynne, all of whom were called up for the Under-23 camp preparing for Olympic qualifiers. Chicago Fire Keeper Matt Pickens was the fifth player who was left out.

Keeper Brad Guzan recorded his first international shutout against Sweden and will look to make his presence felt against Mexico. The 23-year old keeper is currently receiving attention from Scottish giants Celtic.

Landon Donovan became the all-time leading scorer for the US last week when he scored his 35th goal against Sweden on a penalty in the 48th minute. Donovan has played against Mexico nine times in his career, scoring four goals. The US has never lost to Mexico when Donovan scores, and has outscored El Tri 8-1 in those games.

"We are very pleased with the work we put in so far this year, and are looking forward to the next challenge against Mexico," Bradley told ussoccer.com.

"We will continue to build on the concepts that we have established during the last year, and we are clearly progressing as a team as we move forward in preparing for the start of World Cup qualifying this summer."

USMNT roster
Keepers - Steve Cronin (LA Galaxy), Brad Guzan (Chivas USA), Will Hesmer (Columbus Crew), Zach Wells (DC United)

Defenders - Dan Califf (Aalborg BK), Jimmy Conrad (Kansas City Wizards), Ramiro Corrales (Brann), Todd Dunivant (Toronto FC), Clarence Goodson (IK Start), Drew Moor (FC Dallas), Michael Parkhurst (New England Revolution), Eddie Robinson (Houston Dynamo)

Midfielders - Kyle Beckerman (Real Salt Lake), Ricardo Clark (Houston Dynamo), Brad Davis (Houston Dynamo), Justin Mapp (Chicago Fire), Jeremiah White (AGF Aarhus)

Forwards - Landon Donovan (Los Angeles Galaxy), Pat Noonan (Aalesund FK), Chris Rolfe (Chicago Fire), Taylor Twellman (New England Revolution)