With a FIFA window for international matches set for March 23-31, here's a running list of MLS players called up to their national teams, to be updated as squads are announced:

United States - at Denmark (3/25), at Switzerland (3/31)

Jozy Altidore (Toronto FC)

Michael Bradley (Toronto FC)

Nick Rimando (Real Salt Lake)

Brek Shea (Orlando City)

Gyasi Zardes (LA Galaxy)

US U-23s - at Bosnia & Herzegovina (3/27), at Denmark (3/31)

Fatai Alashe (San Jose Earthquakes)

Christian Dean (Vancouver Whitecaps)

Luis Gil (Real Salt Lake)

Boyd Okwuonu (Real Salt Lake)

Shane O'Neill (Colorado Rapids)

Khiry Shelton (New York City FC)

Oscar Sorto (LA Galaxy)

Wil Trapp (Columbus Crew SC)

US U-20s - at England (3/29)

Marky Delgado (Toronto FC)

Conor Donovan (Orlando City)

Bradford Jamieson IV (LA Galaxy)

Erik Palmer-Brown (Sporting Kansas City)

Tommy Thompson (San Jose Earthquakes)

Canada - vs. Guatemala (3/27), at Puerto Rico (3/30)

Sam Adekugbe (Vancouver Whitecaps) -- withdrew due to injury

Kyle Bekker (FC Dallas)

Marcel de Jong (Sporting Kansas City)

Cyle Larin (Orlando City)

Chris Mannella (Toronto FC)

Karl Ouimette (New York Red Bulls)

Quillan Roberts (Toronto FC)

Russell Teibert (Vancouver Whitecaps)

Maxim Tissot (Montreal Impact)

Belgium - Euro 2016 qualifiers vs. Cyprus (3/28), at Israel (3/31)

Laurent Ciman (Montreal Impact)

Cameroon - at Indonesia (3/25), at Thailand (3/30)

Ambroise Oyongo (Montreal Impact)

Costa Rica - vs. Paraguay (3/26), at Panama (3/31)

Waylon Francis (Columbus Crew SC)

Alvaro Saborío (Real Salt Lake)

El Salvador - Argentina (3/28), Guatemala (3/31)

Darwin Cerén (Orlando City)

Ghana - Senegal (3/27), Mali (3/31)

David Accam (Chicago Fire)

Guatemala - Canada (3/27), El Salvador (3/31)

Moisés Hernández (FC Dallas)

Marco Pappa (Seattle Sounders)

Elías Vásquez (Real Salt Lake)

Honduras - Gold Cup qualifiers at French Guiana (3/25), vs. French Guiana (3/29)

Roger Espinoza (Sporting KC)

Boniek Garcia (Houston Dynamo)

Luis Garrido (Houston Dynamo)

Iraq - vs. DR Congo (3/28), vs. DR Congo (3/31)

Justin Meram (Columbus Crew SC)

Ireland - Euro 2016 qualifier vs. Poland (3/29)

Robbie Keane (LA Galaxy)

Jamaica - vs. Venezuela (3/27), vs. Cuba (3/30)

Giles Barnes (Houston Dynamo)

Kemar Lawrence (New York Red Bulls)

Darren Mattocks (Vancouver Whitecaps)

Alvas Powell (Portland Timbers)

Dane Richards (New York Red Bulls)

Jermaine Taylor (Houston Dynamo)

Je-Vaughn Watson (FC Dallas)

Romario Williams (Montreal Impact)

Mexico U-20s

Jesse Gonzalez (FC Dallas)

Panama - at Trinidad & Tobago (3/27), vs. Costa Rica (3/31)

Jaime Penedo (LA Galaxy)

Blas Pérez (FC Dallas)

Portugal U-20s - vs. Uzbekistan (3/27), vs. Uruguay (3/31)

Rafael Ramos (Orlando City)

Estrela (Orlando City)

St. Kitts & Nevis - 2018 World Cup qualifiers vs. Turks & Caicos (3/23), at Turks & Caicos (3/26)

Atiba Harris (FC Dallas)

Scotland - vs. Northern Ireland (3/25), Euro 2016 qualifier vs. Gibraltar (3/29)

Shaun Maloney (Chicago Fire)

Slovakia - Euro 2016 qualifier vs. Luxembourg (3/27), friendly vs. Czech Republic (3/31)

Adam Nemec (New York City FC)

Trinidad & Tobago - vs. Panama (3/27)

Kevin Molino (Orlando City)