The March 26 and 29 FIFA dates are likely to provide an early test of depth for a number of MLS teams.

Hardest hit will be the New York Red Bulls, who are losing six players to international call-ups. In addition to US camp invitees defender Tim Ream and forward Juan Agudelo, New York are also losing Jamaican midfielder Dane Richards, Costa Rican defender Roy Miller, Mexico captain Rafa Márquez and Senegalese goalkeeper Bouna Coundoul.

All six are expected to miss the March 26 clash with the Columbus Crew. The two teams have won the last three Eastern Conference regular-season titles and met in the 2008 MLS Cup Final.

Márquez, a midfielder for El Tri but likely to spend 2011 as a defender for the Red Bulls, will be looking for his 98th and 99th caps as Mexico take on Paraguay and Venezuela in California.

Agudelo, who turned 18 in the offseason, was expected to be a part of the US U-20 team whose World Cup qualifiers begin on March 28 and run through the beginning of April. Instead, the youngster looks to have already won a regular role in Bradley’s senior national team thanks to strong performances in friendlies against South Africa and Chile this winter.

Fellow Eastern Conference hopefuls Sporting Kansas City will also be shorthanded, losing Jamaican defender Shavar Thomas, Guadaloupe midfielder Stephane Auvray and Sierra Leone attacker Kei Kamara, who led KC with 10 goals last season. Sporting are scheduled to travel to Chicago on the March 26 to take on the Fire in a game to be nationally broadcast on TeleFutura.

Sporting Designated Player Omar Bravo was not called up to the Mexican squad and will likely lead the KC line that was already without American striker Teal Bunbury, who is nursing an injury.

Elsewhere, new Houston Dynamo defender Jermaine Taylor will join Richards in the Jamaican camp. Taylor has been a starter for Houston through most of preseason, solidifying a defense that conceded 49 goals in 2010, second-worst in the league.

Also called in for Jamaica is San Jose Earthquakes’ veteran midfielder Khari Stephenson and Jamaican striker Omar Cummings. Stephenson returned to MLS from Norway in 2010 and impressed enough to warrant a new contract for 2011. The central midfielder is expected to be a key cog in Frank Yallop’s new 4-3-3 formation.

Cummings was one of the top players for the 2010 MLS Cup champion Colorado Rapids. The striker is a key cog for both the Reggae Boyz and the Rapids. He will miss Colorado's trip to Chivas USA.

In addition to Ream and Agudelo, the other Amrericans called up for the US matches with Argentina and Paraguay are Vancouver Whitecaps defender Jay DeMerit and LA Galaxy attacker Landon Donovan. DeMerit will miss the 'Caps match against the Union at Philadelphia, while Donovan will be absent for the Galaxy's trip to Rio Tinto stadium to take on Real Salt Lake.

Also missing from that LA vs. RSL clash will be Salt Lake's Savadoran attacker Arturo Alvarez, who was called in for Los Cuscatlecos, RSL's Costa Rican Designated Player Alvaro Saborio, who will join Miller with the Ticos, and Canadian midfielder Will Johnson who heads to Turkey to face Belarus.