In an interview with Goal.com, the Mexican-born midfielder said his heart was with El Tri, but he wouldn't turn down a chance to play for the United States.
But what if Mexico and the United States approached him at the same time?
"I have to go by my heart and it says it would be Mexico," Baca told Goal.com's John Rojas. "I support El Tri, watch all the games and would love to help the team. But if the USA calls me I will be happy too, because this is my second home. I love this culture too and it would be nice to pay that back giving everything for the national team."
But the midfielder, who has been a key part of San Jose's push for the Supporters' Shield this season, said that he wasn't holding out, and would suit up for the Yanks if called upon.
"I wouldn't need to wait for anything," he said. "I'd take the call-up and go all the way for the United States. If I look at my life, I have been in the USA more years than in Mexico. I was educated here, and here is where I play, so it would be an honor and I wouldn't make anybody wait."
The 23-year-old also talked about San Jose's current season. The Quakes have the best record in MLS, and are favorites to win both the Supporters' Shield and the MLS Cup.
"Yes, if we keep working the way we are doing it this year, yes," he responded when asked if San Jose has what it takes to raise the Phil Anchutz trophy. "But we need to go step by step and recognize that even being first during regular season doesn't give us anything in the postseason. All teams will start from scratch and that is dangerous."
Asked which MLS teams he saw as the biggest threat to San Jose's title hopes, Baca identified Sporting Kansas City and the LA Galaxy, who play the Earthquakes on Sunday.
"Kansas [City] is a complete squad with a style that gave us trouble all year. They are a compact team. The Galaxy, they are coming back and their players could be the most dangerous in postseason."
Baca also touched on his club future, with Mexican side Santos in his sights.
"I see myself playing in other leagues," he admitted. "If you want to grow you have to play with the best players. I would love to play in Mexico or Spain.
"In Mexico the first team that comes to my mind is Santos. They play a nice style and I love that. Of course in Europe Barcelona is the best, but to be at that level there is a lot of work to do first."
John Rojas contributed additional reporting
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