Carlos was a pitcher for the University of Northern Colorado team that participated in the 1960 College World Series.

The White Sox were eliminated from the race in the final days of the season, but not before Carlos won two games to keep them in contention.

Four days later, Carlos shut out the Cleveland Indians 4–0 in ten innings, the ChiSox winning the game on Don Buford's grand slam in the bottom of the tenth.

Carlos was featured along with future Hall-of-Famer Johnny Bench on the front cover of Sports Illustrated as one of "The Best Rookies of 1968."

Carlos pitched mostly in relief in 1969 and, after posting a 4–3 record with a 5.66 ERA, was purchased by the Washington Senators on August 25, two years to the day of his Major League debut.