Grimes signed with the Colorado Foxes of the American Professional Soccer League (APSL) in 1990.
[1] The St. Louis Storm of the MSL drafted Grimes in 1991 but he left for Iceland where he spent the 1991 season with Tindastoll FC.
[5] In 1995, Grimes then moved to the USISL Raleigh Flyers where he played with former MLS coach, Jason Kreis.
In January 1996, the San Jose Clash of Major League Soccer (MLS) selected Grimes in the sixteenth round (158 overall) in the Inaugural Player Draft.
After starting 11 of 12 pre-season matches, Grimes injured his shin and the Clash released him on April 20, 1996.
While at SMU, Lothar Osiander called Grimes into the senior national team camp.
In 2017, Grimes had 18 of his former Cal players actively playing professional soccer in the United States and Europe.
In addition, he won his 203rd game the same season and is now the all-time winningest coach in Cal soccer history.
At the time of his retirement, 17 of his former Cal players were playing professionally (8 in MLS, 6 in USL & 3 in NISA).