(Times/ROBERT J GURECKI)

Next Wednesday, Aug. 15, is one of FIFA’s preordained international friendly days. They’re fun for soccer fans, bad news for contending clubs.

That being said, Union manager John Hackworth said there’s a chance centerback Carlos Valdes (Colombia) and midfielders Keon Daniel (Trinidad and Tobago) and Gabriel Gomez (Panama) might get call-ups for their respective nations’ senior teams.

The biggest absence to fill would be that of Valdes, the club’s captain and one of its All-Stars. This would be Valdes' first national-team call-up since 2010, prior to joining the Union.

“We’ve got to figure that out with Carlos,” Hackworth said. “We’re still trying to finalize his travel plans with the Colombian federation. Hopefully, he’s available for us Sunday. If he’s not, we’ll deal with that.”

Assuming Bakary Soumare is fit --- for real, this time, as opposed to when Hackworth said a week ago that he'd be ready for selection against Montreal -- there shouldn't be an issue. But if the Union have to go with a central defense tandem of Amobi Okugo, a natural midfielder who was played well above average at centerback, and rookie Ray Gaddis, that could create problems. There's also Sheanon Williams to slide into that spot, too. So plenty of options, but having Valdes is the best one.

July should be an exciting month to spend some time on the Chester waterfront.

In addition to three of the Union's five matches in July being contested at PPL Park, the team announced Tuesday that it will host English Premier League side Aston Villa July 18 at 7:30 p.m. for an international friendly.

Oh, and PPL Park serves as the host of this season's MLS All-Star Game, to be played July 25. Not bad, huh?

As for ticket details, the Union said tickets to the friendly with Aston Villa -- the very same club with which Union forward Danny Mwanga spent 10 days during preseason training -- will be available for purchase today, Tuesday, March 27, beginning at 4 p.m. That's assuming you don't possess a season-ticket plan. (Season-ticket holders with cards will have the game loaded onto their cards, while those who opt for printed tickets will have them in the mail by June. As for parking, the club said there's a 'bonus game' parking pass in every season-ticket holder package that can be used for this match.)

“It’s our ongoing commitment to bring world-class international competition to Philadelphia,” said Union CEO Nick Sakiewicz in a statement. “We are very proud to host Aston Villa in what will be a challenge for our club and a treat for our fans. We’re also thrilled that this match will be a wonderful precursor to the 2012 MLS All-Star Game and its surrounding festivities. This will certainly be an amazing week for not only our fans and PPL Park but also for cities of Chester and Philadelphia.”

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Also, one other note: Because the United States U-23s endured a 3-3 draw Monday night against El Salvador, they finished third in their pool and will not qualify for the 2012 Summer Olympics.

Therefore, the returns of midfielders Freddy Adu and Amobi Okugo, as well as right back Sheanon Williams to the Union's locker room will be sooner than expected.

Waiting on official word from the club regarding their availability for this weekend's match against Vancouver, but a team official said the trio -- in theory -- should return to the Union Wednesday (Tuesday was their travel day) and should be available to play Saturday, barring anything unforeseen.

(Times staff photo / ERIC HARTLINE)

The U.S. national team callup of right back Sheanon Williams caught the Union by surprise, but it's not unprecedented nor was it out of the question.

And according to an official from U.S. Soccer and another from Major League Soccer, Union boss Peter Nowak wouldn't have been in wrong to block Williams' late callup to join the U.S. U-23s for a CONCACAF Olympic Qualifying tournament. Nowak had said Wednesday “it's not possible” to block Williams' callup.

“Because this tournament is not on a FIFA international date, there is no requirement for a club here or in Europe to release players,” Neil Buethe, the communications coordinator for U.S. Soccer said to me Wednesday. “On a related note, I will say MLS has been very supportive of permitting players to participate for qualification tournaments in the Olympics and World Cup.”

“There's always been a symbiotic relationship between U.S. Soccer and MLS,” Will Kuhns, Major League Soccer's director of communications, told me Wednesday, “but there is no requirement.”

Nowak was unnerved Wednesday during a press conference at PPL Park, where he said he detested Williams' callup to join the U-23s despite missing the training camp that precipitated the Olympic qualifying tournament.

According to the U.S. Soccer and MLS officials, Nowak would have had ground to stand on to block Williams' callup. But, let's be honest, even if Nowak was surprised by the timing of Williams' callup, what coach is going to stymie a player's national-team visibility and progress?

“Everybody got caught by surprise because Sheanon wasn't in the last two camps with the national team, with the U-23s,” Nowak said. “It was communicated by the coach at the end of the January camp … and we saw the final roster – not the final roster, but the roster that was called a day after the Portland game that Sheanon might not be in the plans for the national team. We didn't have any kind of indication during that time that he might be called up last minute.

“Our understanding was that – and I was part of this process four years ago (as an assistant coach) – you take the numbers and players (so) that, if something happens, you have enough players in camp that you don't move anybody from outside the pool that you have,” added Nowak. “It was a drastic change. He wasn't with the team for 10 days. It's a little bit of an adjustment for all of us.”

Without Williams, the Union will have to look elsewhere for support on the right side of the backline for Saturday's match at Chicago. It's yet to be determined what the defensive four will look like, especially considering the Danny Califf scenario and Porfirio Lopez's callup earlier this week.

Williams, and Union teammates Freddy Adu and Amobi Okugo continue their time with the U.S. U-23s through next week.

(Times staff photo / JULIA WILKINSON)

As if beginning the season 0-2-0 wasn't difficult enough, the Union were dealt another blow late Tuesday night, when right back Sheanon Williams got word that he'd received a call-up for national duty.

Williams (pictured, left, with Freddy Adu) will fly to Nashville Wednesday morning to join the U.S. U-23s, who christen their Olympic qualifying tournament Thursday with a 9 p.m. match against Cuba. Union teammates Freddy Adu, the U-23 captain, and Amobi Okugo are already in Nashville.

A defender, Williams inked what he told reporters is a five-year contract extension this offseason. In doing so, the Union locked up a rising talent on the national circuit ... which makes the notion of losing Williams for as many as the next two games a concern.

Williams, who had been in the U-23 camp this offseason, along with Adu and Okugo, will miss Saturday's match at Chicago and stand to miss the March 31 date against visiting Vancouver, assuming the U-23s advance to the CONCACAF semifinal and beyond.

Following Thursday's match with Cuba, the U.S. U-23s take on Canada Saturday, then El Salvador the following Monday, March 26. The semifinal and final matches are March 31 and April 2.

Already a weak link for the Union, the backline would suffer a serious hit if Williams was to miss the next two matches. The Union have relinquished five goals in two matches, both defeats, to open their season. No team in Major League Soccer has surrendered as many.

And with Danny Califf's status unknown -- at least until Wednesday, when Union manager Peter Nowak addresses the media -- the backline has a serious hole.

(Times staff photo / JULIA WILKINSON)

Just got word that left back Porfirio Lopez received a call-up Tuesday to join the Costa Rican national team. But fear not, Union fans. Lopez will rejoin the Union Thursday, in time for the club's match Saturday in Chicago.

Lopez will compete with Costa Rica against Jamaica in an international friendly Wednesday at 8 p.m. at National Stadium in Kingston, Jamaica. He'll rejoin the Union Thursday.

That Lopez will not miss a match is the good news for the Union, who had pined for an anchor at left back since trading Jordan Harvey to Vancouver last season. And Lopez is it. He has played 90 minutes in each of the Union's first two games of the season. Gabriel Farfan, a natural midfielder, filled in well the rest of the 2011 season until the Union made signing Lopez a priority during the offseason.

Lopez has only one cap with Costa Rica, debuting Aug. 10, 2011 in a friendly against Ecuador, during which he started and played 73 minutes in a 2-0 loss.

(Times staff photo / JULIA WILKINSON)

Union midfielder Freddy Adu has been named the team captain for the United States' U-23 team, in advance of its Summer Olympics qualifying tournament later this month, according to SI.com soccer reporter Grant Wahl.

Neither U.S. Soccer nor the Union have made an announcement regarding the captaincy.

Adu, Union teammate Amobi Okugo and the rest of the U-23s are expected to finalize their rosters by Tuesday. The CONCACAF Olympic Qualifying tournament begins Thursday in Nashville, with the U.S. partaking in Group A. The semifinal and final matches will be played at LIVESTRONG Sporting Park in Kansas City, Kan., March 31 and April 2, respectively.

Adu and Okugo stand to miss two more matches for the Union. They flew to Nashville following the Union's March 12 loss at Portland and missed Sunday's home-opening loss to Colorado.

Adu being named captain to the club is a far cry from two weeks ago, when he told me prior to the Union's season opener that he'd be thankful just to get a call-up to the team. Maybe that's just Adu being the consummate team guy who's unwilling to ruffle any feathers, but it sounded genuine. He really wanted to be on this team, and now he's its captain.

“Sure, it would (be great)," Adu said of a potential call-up. "You give it your all and have a pretty good idea where you stand with the team. I'd love to be a part of that team. That's a goal of mine. At the end of the day, if I am with the Olympic team ... it'll be great."

(Photo / Associated Press)

PORTLAND, Ore. -- It would've been easy for Freddy Adu to allow his mind to wander, but the 22-year-old midfielder insisted Monday night that he was focused on one thing: winning.

In the moments following the Union's 3-1 season-opening loss to the host Timbers, Adu discussed the news that he received prior to the game -- that he would be joining the United States U-23 team for its final training camp prior to Olympic qualifying.

“You've got to adjust. You've got to be ready for anything," Adu said about his call-up. "… I'm excited. Hopefully we can qualify for the Olympics.

As for whether Adu, who played 74 minutes and was subbed out for Jack McInerney, had his mind elsewhere while playing at JELD-WEN Field... umm, quite the contrary, he said.

“I wasn't thinking about it at all," Adu said. "I was completely focused on Philadelphia and what we're trying to do here and focused on getting the win."

Of course, what the Union are trying to do could suffer a blow with Adu gone for what could amount to the next three matches. Adu and fellow Union midfielder Amobi Okugo ship out to Nashville to join the U-23s directly from here in Portland.

PORTLAND, Ore. -- Midfielders Freddy Adu and Amobi Okugo got word Monday that they will head to Nashville following tonight's season opener with the Union, having received call-ups to the United States U-23's final training camp in advance of its Olympic qualifying tournament.

Per MLS policy, players are not available for comment prior to matches, so I'll try to snag comments from either Adu or Okugo (or both) afterward.

The U.S. club will compete in Group A in the CONCACAF Olympic Qualifying tournament, which kicks off March 22 at LP Field in Nashville. Adu and Okugo could miss three matches with the Union, should the U.S. side require their services for that long. Those matches are: March 18 vs. Colorado; March 24 at Chicago and March 31 vs. Vancouver.

Here's a look at the rest of the roster:

GOALKEEPERS (2): Bill Hamid (D.C. United; Annandale, Va.), Sean Johnson (Chicago Fire; Lilburn, Ga.)

DEFENDERS (6): Josh Gatt (Molde; Plymouth, Mich.), Perry Kitchen (D.C. United; Indianapolis, Ind.), Ike Opara (San Jose Earthquakes; Durham, N.C.), Kofi Sarkodie (Houston Dynamo; Huber Heights, Ohio), Zarek Valentin (Montreal Impact; Lancaster, Pa.), Jorge Villafaña (Chivas USA; Anaheim, Calif.)

MIDFIELDERS (6): Freddy Adu (Union; Potomac, Md.), Joe Corona (Club Tijuana; Chula Vista, Calif.), Mix Diskerud (Gent; Oslo, Norway), Jared Jeffrey (Mainz; Richardson, Texas), Amobi Okugo (Union; Sacramento, Calif.), Michael Stephens (LA Galaxy; Naperville, Ill.)

FORWARDS (5): Juan Agudelo (New York Red Bulls; Barnegat, N.J.), Terrence Boyd (Borussia Dortmund; Berlin, Germany), Teal Bunbury (Sporting Kansas City; Prior Lake, Minn.), Joe Gyau (Hoffenheim; Silver Spring, Md.), Brek Shea (FC Dallas; Bryan, Texas)