However, on October 17, 1960, the National League granted an expansion franchise to the Houston Sports Association in which their team could begin play in the 1962 season. According to the Major League Baseball Constitution, the Houston Sports Association was required to obtain territorial rights from the Houston Buffaloes in order to play in the Houston area, and again negotiations began to purchase the team. Eventually, the Houston Sports Association succeeded in purchasing the Houston Buffaloes, at this point majority-owned by William Hopkins, on January 17, 1961. The Buffs played one last minor league season as the top farm team of the Chicago Cubs in 1961 before being succeeded by the city’s NL club.

The new Houston team was named the Colt .45s after a “Name The Team” contest was won by William Irving Neder. The Colt .45 was well known as “the gun that won the west.” The colors selected were navy blue and orange. The first team was a group of scrubs formed mostly through an expansion draft after the 1961 season. The Colt .45s and their expansion cousins, the New York Mets, took turns choosing players left unprotected by the other National League franchises.

Just on the horizon, the structure of the new domed stadium was more prevalent and it would soon change the way that baseball was watched in Houston and around the league. On December 1, 1964, the team announced the name change from Colt .45s to “Astros.