Complex sentence: Russell then left the Dodgers, severing a 30-plus year association, coached for the Tampa Bay Devil Rays and managed farm teams of both Tampa Bay and the San Francisco Giants, the Dodgers' archrivals.
Split into simpler sentences: Russell then left the Dodgers, severing a 30-plus year association. He then coached for the Tampa Bay Devil Rays and managed farm teams of both Tampa Bay and the San Francisco Giants, the Dodgers' archrivals.