Luis Martir is considered a promising young defender, so the fact that the Los Angeles native is playing for the United States U-20 team shouldn't be notable, but it is. Martir is part of the Chivas de Guadalajara academy, and the club bars its players from playing for anyone other than Mexico.
Chivas has long had a Mexicans only policy. They relaxed it in recent years so anyone with Mexican parents could play for the club, even if they weren't born in Mexico, but they remained firm on one thing: that player must identify as Mexican and therefor could not play for another country's national team.
That has been a problem for the U.S., which has a slew of Mexican-Americans, some of whom go to Mexico to play. It's resulted in some players opting to play for Mexico over the U.S., while others, like Omar Salgado, chose the U.S. and were released by Chivas.
Martir is considered a promising young defender and some have said that he is good enough to make the Chivas senior team in the next few years, but he has long been leaning towards the U.S. In July, he was named to a U.S. U-20 roster, only to later be dropped. No reason was given at the time, but it is possible that Chivas pressured him into dropping out.
This time around, Martir did not drop off the U.S. roster. He didn't just show up to train either -- he played in a match. Now the attention turns to Chivas, who have to decide how strictly they are going to enforce their Mexicans only rule. Martir may be searching for a new club.