Castillo missed the season’s final two months as the Revolution made a push into the playoffs under new manager Bruce Arena. Castillo said he has fully recovered.

Those two factors combined to result in Castillo not returning to the club. An attacking fullback or wingback who is a good crosser and dribbler, he finished with five assists in 20 games. That total was seventh-most among defenders last season. It was the second consecutive season that he notched five assists after also doing so for Colorado in 2018.

Castillo grew up in New Mexico and took a circuitous route to MLS. He signed with Santos Laguna in Mexico when he was 16 after attending an open tryout. Castillo’s parents grew up as Santos Laguna supporters because they are from the Torreon, Coahuila area of Mexico.

Castillo helped Santos Laguna win the Clausura title in 2008. He was sold to Club America, one of the biggest clubs in the Western Hemisphere. Los Aguilas, as Club America also is known, sent him on a series of loans to Tigres, San Luis, Puebla and then to Tijuana, which bought him and which he helped win the Apertura title in 2012. Tijuana sold him to Atlas, which then sold him to Monterrey in 2015. He made 43 appearances for Monterrey, which loaned him to Colorado in 2018.

His experience in Mexico and as one of two players who have been capped by Mexico and the U.S. should help the club in the Champions League. Should Atlanta United advance past Honduran power Motagua, it likely will face Club America in the next round.

Castillo has lived a nomadic soccer life and hopes he can put down some roots with Atlanta United.

“I’ve been around big clubs, small clubs; it doesn’t matter,” he said. “How you grow up and mature and do things right on the field and off the field. I’m 33, and I think I’ve matured past that. That’s why I chose Atlanta. I hope I get to stay here for many years.”

The club’s history and luck with left backs doesn’t make that seem probable. The team has cycled through left backs and wingbacks at a dizzying pace: Greg Garza, Chris McCann, Mikey Ambrose, Bello, Brek Shea, Flo Pogba and Justin Meram.

Only Bello, a Homegrown signing, remains with the team. Castillo is here to help him learn and help Atlanta United keep winning.

“That’s why he (Bocanegra) brought me in,” Castillo said. “I know he will get some playing time. I’m here to do my things and help him as a player to learn.”