Kirby again split 1988 between Bakersfield and San Antonio, but this time 100 of his 112 total games were with San Antonio. His overall numbers declined, as he batted .244 with 25 runs batted in and 35 steals. In 1989, Kirby saw action in 122 games, 44 with San Antonio and 78 with the Triple–A Albuquerque Dukes. In total, he hit .302, drove in 37 runs and stole 40 bases. Kirby remained with Albuquerque in 1990. In 119 games, he batted .278 and totaled 30 RBI and 29 steals. Curiously, he had compiled the same number of RBI and stolen bases in his 78 games with Albuquerque the prior season.