On Sunday afternoon, Juergen Klinsmann will announce the U.S. national team roster for next Wednesday’s friendly against Mexico at Azteca Stadium. Klinsmann has already assembled a preliminary list, contacting players and clubs, and will select a final roster of about 23 for the match.

Players will begin arriving in Mexico City on Sunday. Eighteen will suit up Wednesday. Six substitutes are permitted in international friendlies.

Roster selection for this one is tricky. Although the match falls on a FIFA fixture date, European-based players are preparing for the start of league play.

The English Premier League, for instance, begins three days later. So would Klinsmann burden a club by requesting a starter for five days leading to the league opener? Presumably, Klinsmann will select at least one goalkeeper from England: Tim Howard (Everton’s first choice) or Brad Guzan (Aston Villa’s second choice) to face El Tri.

Germany, on the other hand, won’t relaunch the Bundesliga season until Aug. 24. Michael Bradley and Roma don’t open until the 26th.

The friendly is important, though, because a pair of 2014 World Cup qualifiers against Jamaica await: in Kingston on Sept. 7 and in Columbus four days later. There aren’t many opportunities during the year to bring the forces together, so Klinsmann would want to assemble most of his regulars.

It’s safe to assume several Mexican-based U.S. players (i.e. Herculez Gomez) will be summoned. In country ahead of camp, Klinsmann plans to attend Mexican league matches this weekend.

Another consideration: It’s a chance to test unproven players in an oppressive environment for possible inclusion deeper in the World Cup cycle. D.C. United’s Chris Pontius (two previous U.S. camps but no caps) would fall into this category.

Even if he didn’t make the game-day roster, Pontius would have Klinsmann’s attention during the short training camp. Pontius (10 goals this season) was included on the preliminary roster, I’m told, but it’s unclear whether he has received the Mexico invitation.

Why is Klinsmann waiting so long to unveil the roster? It’s his personal preference, and it’s going to be standard during his U.S. tenure. Gamesmanship is part of it, but the late announcement also keeps the focus on the players who are actually in camp and not on those who might’ve been named and then replaced at the last minute because of an injury suffered with their club.

I don’t fully understand this reasoning — why not create some buzz a week ahead of the match? -- but that’s the way it’s going to be.

TV for the Mexico match: ESPN2, Univision and ESPN3.com Wednesday at 8 p.m. ET.