During the early 1920s, Najo's Milmo Bank team occasionally traveled to San Antonio, Texas for games against semi-pro teams there. During one of these visits, Najo was "discovered" by a scout with the San Antonio Bears of the Class A Texas League. He was signed in December 1923 and played his first pro game on April 16, 1924 at San Antonio's League Park, leading off and playing right field for the Bears against the Galveston Sand Crabs. By his participation in that game, he became one of the first Mexicans to play U.S. professional baseball. Baseball historians also believe Najo was the first Mexican to play in the Texas League, which was established in 1888.