For the first time since Week 1, all 20 MLS teams will be in action. In theory, that's great. However, nearly every team is impacted by the league's insistence on playing through the FIFA international fixture window. With teams required to release players who are called up by their respective senior national teams, it creates an added managerial hurdle and takes away from some of the more high-profile games on the league's schedule (see: FC Dallas-Seattle, Real Salt Lake-Toronto FC).
It offers an opportunity for other players to step up, seize the limelight and potentially create bigger roles for themselves down the road, but it also does a disservice to fans hoping to see teams at their best.
Game by game, here's how the Week 4 MLS slate will be impacted by the FIFA window and youth national team call-ups (all times Eastern):
New England Revolution vs. San Jose Earthquakes, 3 p.m.
The U.S. youth national teams are the only ones affecting this clash, although if not for injuries and Jurgen Klinsmann's personal preference, it could have been a lot worse. Jermaine Jones (who just returned to training) is still out for the game even though he's not with the national team. Lee Nguyen was not called in by Klinsmann, though, so he'll suit up for the Revs.
Two of the Earthquakes' rising stars will be gone, though, as Tommy Thompson and rookie Fatai Alashe, who scored the first official goal in Avaya Stadium history, will be representing the U.S. U-20s and U-23s, respectively.
Montreal Impact vs. Orlando City SC, 4 p.m.
No team is hit as hard as Orlando City. The Lions could have as few as 13 active field players available, according to the Orlando Sentinel. Kaká will be one of them, but Brek Shea (USA), Kevin Molino (Trinidad & Tobago), Cyle Larin (Canada), Darwin Ceren (El Salvador), Conor Donovan (U.S. U-20), Rafael Ramos and Estrela (Portugal U-20s) will all be out. Shea, Molino and Ceren are would-be starters for Adrian Heath's club, which is looking to bounce back from its first loss in its short MLS existence.
Montreal, meanwhile, has been devastated by long-term injuries to Justin Mapp and rookie sensation Cameron Porter, and the league's last remaining hope in the CONCACAF Champions League will also be without starting center back Laurent Ciman, who is off with Belgium in Euro 2016 qualifying. Teammates Maxim Tissot (Canada), Ambroise Oyongo (Cameroon) and Romario Williams (Jamaica) are away as well.
Needless to say, the next time these teams match up, the lineups will be vastly different.
New York City FC vs. Sporting Kansas City, 7 p.m.
NYCFC returns to Yankee Stadium, but it will do so without Slovakian forward Adam Nemec, who has started each of the club's three games. His chief replacement, rookie Khiry Shelton, is away with the U.S. U-23s. That leaves Jason Kreis with a selection headache atop his formation, although he was spared by Klinsmann leaving central midfield cog Mix Diskerud off his USA roster. Patrick Mullins and Tony Taylor are Kreis's options to pair with David Villa.
Sporting KC, meanwhile, has taken a hit to its midfield, with Roger Espinoza representing Honduras. Its defensive depth is depleted some as well, with Marcel de Jong (Canada) and Erik Palmer-Brown (U.S. U-20s) on international patrol.
D.C. United vs. LA Galaxy, 7 p.m.
The two franchises with the most MLS Cups in league history go head-to-head at RFK Stadium for their only meeting of the season, but its hardly a full-strength fight. The reigning champs are without reigning MVP Robbie Keane and rising star Gyasi Zardes, who are with Ireland and the U.S. men's national team, respectively.
Alan Gordon and Jose Villarreal (who turned down a U.S. U-23 call-up to stay with the Galaxy) will be looked upon to fill their shoes, but that's a lot of production to fill–Keane and Zardes combined for 35 goals and 16 assists a season ago. The Galaxy are also without Jaime Penedo, who is off with Panama, and U.S. U-23 fullback Oscar Sorto and U.S. U-20 forward Bradford Jamieson IV.
D.C. United isn't hit by the international break, but forwards Eddie Johnson (long-term health problem) and Fabian Espindola (suspended) remain out.
Columbus Crew vs New York Red Bulls, 7:30 p.m.
The Crew are down three potential starters, with U.S. U-23 midfielder Wil Trapp, fullback Waylon Francis (Costa Rica) and forward Justin Meram (Iraq) all unavailable.
The Red Bulls are missing three players as well, but their starting lineup should be mostly spared. Karl Ouimette (Canada), Dane Richards and Kemar Lawrence (Jamaica) being out means Jesse Marsch has fewer options from which to choose. Lawrence did start in central defense in last week's 2-0 win over D.C.
Vancouver Whitecaps vs. Portland Timbers, 8 p.m.
Vancouver misses Darren Mattocks (Jamaica), Christian Dean (U.S. U-23s), Russell Tiebert and Sam Adekugbe (Canada) for the first Cascadia Cup clash of the season. That doesn't include the suspension to Uruguayan center back Diego Rodriguez for grabbing Aurelien Collin, uh, between the legs in last week's match in Orlando.
The Timbers are only missing Jamaican fullback Alvas Powell, but they must still overcome long-term injuries to midfield stalwarts Will Johnson and Diego Valeri in hopes of finally getting over the draw hump. The club has tied its first three games of the season.
Houston Dynamo vs. Colorado Rapids, 8:30 p.m.
Owen Coyle has some lineup shuffling to do, as the Dynamo are without Hondurans Oscar Boniek Garcia and Luis Garrido and Jamaicans Jermaine Taylor and Giles Barnes. For Barnes, born in the UK, it's his first call-up to the Jamaican national team.
Colorado's only absence is U.S. U-23 defender Shane O'Neill. The Rapids are 0-0-2 and have yet to score or concede yet this season. Houston's not an easy place to play, but they'll have a leg up with the Dynamo's missing pieces.
FC Dallas vs. Seattle Sounders, 8:30 p.m.
FC Dallas is the league's only 3-0-0 team, and Seattle is the reigning Supporters' Shield winner and one of the odds-on favorites to win MLS Cup. The two met in a playoff series last year decided only by away goals. This should be a spectacle for the country to behold.
Unfortunately, some of the heaviest hitters in both MLS and CONCACAF are out. Seattle star Clint Dempsey would have missed the match for international duty anyway, but he tweaked a hamstring in U.S. training, and will be out for another couple of weeks. Fellow starter Marco Pappa is off representing Guatemala.
FC Dallas star striker Blas Perez, meanwhile, is off representing Panama.
Teammates Atiba Harris (St. Kitts & Nevis), Moises Hernandez (Guatemala), Kyle Bekker (Canada), Je-Vaughn Watson (Jamaica) and Jesse Gonzalez (Mexico U-20s) are out, too.
Making matters more unfortunate, the Western Conference foes only play against each other one more time, and it's during the next FIFA international break. Dempsey will likely be just three days removed from facing World Cup champion Germany.
From the looks of things, two of the top teams in the league might not face each other at full strength at all in 2015, unless they have a postseason rematch.
Chicago Fire vs. Philadelphia Union, (5 p.m., ESPN2)
Chicago, the league's only team without a single point, is in need of a spark. The Fire will have to get it without two of its three new Designated Player signings, as Shaun Maloney (Scotland) and David Accam (Ghana) are unavailable, taking some of the star power away from this nationally televised game.
Philadelphia, another side looking for its first win, is not impacted at all by the FIFA window.
Real Salt Lake vs. Toronto FC (7 p.m., FoxSports1)
Four of the biggest names who would have been involved in this game miss out. Toronto FC's Jozy Altidore and Michael Bradley and Real Salt Lake goalkeeper Nick Rimando are off with the USMNT, and Alvaro Saborío is with 2014 World Cup quarterfinalist Costa Rica meaning this nationally televised, inter-conference clash loses a large chunk of its luster.
RSL is also without U.S. U-23ers Luis Gil and Boyd Okwuono and Guatemalan center back Elias Vasquez, while TFC misses Canadians Quillan Roberts and Chris Mannella and U.S. U-20 midfielder Marky Delgado (combined for no 2015 appearances thus far).
Kyle Beckerman (USA) and Sebastian Giovinco (Italy) were not called in by their respective national teams, and they'll headline the match–which features Robbie Findley's return to Salt Lake–of these less-than-full-strength foes. The only other time they'd be able to meet at full strength in 2015 would be MLS Cup.