Alvarez, born in Houston, Texas, represented the United States at various youth levels, before making his full national team debut for El Salvador on August 12, 2009, in a World Cup qualifier against Trinidad & Tobago. His one goal in 20 international appearances came in a 6-1 win over at the 2011 CONCACAF Gold Cup.

"I felt that the time had come to try myself out in Europe last year, which is why I moved to Portuguese club Paços de Ferreira," Alvarez told the Videoton website. "I am pleased to have joined a strong club like Videoton FC.

"I hope that I can help my new team out with my play, goals and by also setting up goals. I also heard from the others that there is usually a great atmosphere at the Sostoi stadium for games. I can hardly wait to make my debut in the colours of Videoton FC!"

The midfielder made his professional debut at 18 for the San Jose Earthquakes of the USA's Major League Soccer. He played FC Dallas from 2005-2008, before returning to San Jose from 2008-2010. Alvarez spent the 2011 season with Real Salt Lake, before moving to Paços de Ferreira last year.

Another Salvadoran international, Rafael Burgos, also plays in Hungary for Kecskeméti. Burgos recently helped El Salvador to a third-place finish at UNCAF Copa Centroamericana.