Simpkins was selected by the
Cincinnati Bengals in the seventh round (167th overall pick) of the
1980 NFL draft. As a rookie, he started two games following an injury to
Glenn Cameron. Simpkins did not appear in any games during the
1981 NFL season. He returned to the Bengals midseason in 1982, appearing in five games as a backup. In 1983, he appeared in 15 games as a backup linebacker. Simpkins finally became a starter for the
1984 and
1985 Bengals, appearing in all 32 games, including 20 games as a starter. After being cut by the Bengals, Simpkins did not play in the NFL during the 1987 season. He signed with the
Green Bay Packers in May 1988. After being cut late in the preseason, he was re-signed by the Packers in late September 1988. He appeared in seven games, all as a backup, for the Packers during the
1988 NFL season. Between 1980 and 1988, Simpkins appeared in 91 NFL games, 22 of them as a starter. ==Later years==