In 1988, he was drafted by the Philadelphia Phillies in the first round (11th overall). He had one "golden" season-that being his first professional year. In 1989, he had reached every level of professional baseball, from A-ball to the major leagues. For the Class A Clearwater Phillies, he went 2-1 with a 1.30 ERA in 6 games. For the Double-A Reading Phillies, he went 8-7 with a very respectable 3.38 ERA in 19 games. For the Triple-A Scranton/Wilkes-Barre Red Barons, he went 3-0 with a 0.37 ERA. Continuing with the Phillies, Combs went 4-0 with a 2.09 ERA in 6 games. Taking his success into consideration, the next year the Phillies placed Combs in the starting rotation. Combs, however, was not able to maintain his streak. He went 10-10 with 4.07 ERA, with 86 walks and only 108 strikeouts. His performance continued to decline and he had an ERA of 7.71 in his final season.
Two times in his professional career Combs walked more than he struck out. In 1991, he walked 43 and struck out 41; in 1992 he walked 12 and struck out 11.