[USA CONFIDENTIAL] There was a lot to be worrying about the USA's 2-0 loss to Canada Saturday in Olympic qualifying -- its first defeat to its neighbors to the north at this level in two decades -- but perhaps the most puzzling aspect of the loss and its aftermath was how unprepared to USA seemed to be for how the Canadians came out.

U.S. coach Caleb Porter admitted as much when he talked about how Canada came out. And we're not talking about how he was "a little surprised" with the seven changes in the Canadian starting lineup or the "Christmas tree" formation -- a 4-3-2-1 -- the Canadians lined up in. "That’s not a shape they’ve used," he said.

As the game unfolded and the Canadians began its concerted assault on the U.S. goal late in the first half, Porter says the USA "was vulnerable and that in some ways rattled us psychologically and then going forward we never got comfortable." Bottom line: the USA looked lost.

Much has been made of the U.S. talent at the U-23 level, making qualifying seem a formality. Sure, there are lots of prospects at this level, but it isn't exactly a deep group, or deep enough to coast through Olympic qualifying.

Indeed, the recent past for this age group is not good. The USA failed to qualify for the 2011 Under-20 World Cup in Colombia and exited in the group stage at the 2009 Under-20 World Cup -- the first time that the USA has failed to advance past the group stage at the U-20 World Cup since 1987.

If you thought Ike Opara had a tough night Saturday against Canada, you should have seen him in Egypt, where he conceded penalties against Cameroon and South Korea and get sent off against South Korea.

While Opara showed some promise with the San Jose Earthquakes, he's only played 19 games in two-plus seasons in MLS because of injuries. His partner in the middle of the U.S. backline, Perry Kitchen, doesn't play there for D.C. United, which uses him as a holding midfielder. In front of them was holding midfielder Jared Jeffrey, who has yet to play a first-team pro league game in three and a half seasons in Europe.

That inexperience is telling when you consider how vulnerable the U-23s looked down the gut against Canada.

But it's up front, on the wings, that the Canada game was lost. The Canadians let the USA try to beat them down the flank and it couldn't.

Brek Shea has perhaps the best best resume of any player on the U-23 squad: 2011 MLS MVP finalist and Best XI pick, and appearances in every game since Jurgen Klinsmann took over as national team coach.

Needing to carry the U-23s against Canada, Shea didn't get the job done. Neither did Freddy Adu, who has the longest resume of any player on the team: 10 years competing for the USA at the age group level!

Of the two German-based players who came on as second-half subs, neither Joe Gyau or Terrence Boyd could break down the Canadian defense. Neither has yet to get off the bench for their respective Bundesliga teams. Both remain prospects, still raw and unproven.

The weekend's results from Nashville and Carson set up the likely scenario that the USA must beat El Salvador and then Mexico to earn its ticket to the London Olympics. A tall order, based on what we've seen Saturday and Sunday from the two venues.

But if the USA does advance, all but two field players might be replaced.

On top of the three overage players who can be used as jokers, there were three sure-fire under-23 starters who were not called in -- Jozy Altidore, Tim Chandler and Danny Williams -- because their commitments to their European clubs and the senior national team took priority.

Alfredo Morales started in last month's friendly against Mexico but did not return from Hertha Berlin for qualifying. Josh Gatt was called up for the Concacaf tournament but left camp to rejoin Molde -- for which he scored the deciding goal in its opening game.

(Also U-23 eligible is Real Salt Lake's Luis Gil, who might have helped in midfield, but he is presumably being held out for the next U-23 cycle.)

Like most decent soccer nations, the USA doesn't throw all its eggs into its Olympic basket.

The lesson of the Canada debacle, though, is that there may have been fewer eggs in the under-23 basket Porter took to Nashville than we previously imagined.