Officially the rule about cleat colors that must currently be followed by the Colorado Rockies and all other 29 Major League teams is as follows…
“At least 51% of the exterior of each Player’s shoes must be the Club’s designated primary shoe color and the portion of the Club’s designated primary shoe color must be evenly distributed throughout the exterior of each shoe.”
Of course, that’s completely arbitrary and practically most teams’ players are held to just wearing one of two colors with stripes or shading that works within the color scheme.