FRISCO, Texas – After a week-and-a-half of training sessions and scrimmages, the US Under-23 national team's friendly against Mexico has finally arrived.

And with Olympic qualifying set to begin in less than a month against Cuba, US head coach Caleb Porter knows that Wednesday’s matchup at FC Dallas Stadium against CONCACAF’s best (10 pm ET, Univision) will help finalize the roster he takes to Nashville, Tenn., on March 22.

“This is kind of the final game we have to get some questions answered prior to selecting our final roster, and also seeing how the group fits together collectively,” Porter told reporters before Tuesday's closed practice. “But we feel good and we think this game is going to be a good measuring stick."

Since opening camp on Feb. 19 in North Texas, the U-23s have balanced training sessions with two scrimmages against FC Dallas and expansion NASL side San Antonio Scorpions, winning the matches 2-1 and 3-0, respectively.

However, even with the two wins Porter was quick to note Mexico’s recent success on the national team level with the Under-17s winning the 2011 U-17 World Cup, the U-20s placing third in Colombia and, most recently, the gold medal finish at the 2011 Pan American games in October.

“Obviously Mexico is a great soccer-playing country,” said Porter. “We know the last couple of games Mexico has defeated the US. We also know in the last 12 years, we know what our record is against them as well, so it’s a great rivalry. We have great respect for Mexico and we are looking forward to the game.”

The US side will be without winger Brek Shea ­­– a goal scorer in both scrimmages with the U-23s ­– as he was summoned to Italy to join the senior team for Wednesday's friendly against the 2006 World Cup champions.

Porter praised the 22-year-old and acknowledged his importance to the squad heading into qualifying.

“It’s exciting for Brek,” he said of the call-up. “He’ll be with us in qualifying. We had the opportunity to integrate him in this camp for the first time. We are very supportive and cooperative and we wish Brek all the best. He’s a very good player and he’s going to be a key guy in qualifying for us.”

But even with Shea’s absence, the arrivals of Alfredo Morales, Joe Gyau, Mix Diskerud and Joe Corona from their European and Mexican club sides will provide an added boost to the roster that includes 15 MLS players.

“It’s nice to get a guy like Alfredo Morales and some others who haven’t been able to get released from their clubs, to get them into camp, and to see how they fit with the group,” Porter said, “and that’s, at the end of the day, what we are looking at.

“We are trying to put the best group together, to put the best team together that when it takes the field, it’s united and plays the way that we think is the best way to play to win our games in qualifying and allow us to qualify for the Olympics.”