Wiktionary
n. (context sports English) At a sporting event, a member of the radio or television announcing team who assists a play-by-play announcer. Provides insight into strategy, player performance, background information, etc., and often light humor.
Wikipedia
A color commentator is a North American term for a sports commentator who assists the main commentator, often by filling in any time when play is not in progress. In other regions this role is variously referred to as an analyst or summariser. The color analyst and main commentator will often exchange comments freely throughout the broadcast, when the play-by-play announcer is not describing the action. The color commentator provides expert analysis and background information, such as statistics, strategy and injury reports on the teams and athletes, and occasionally anecdotes or light humor. Color commentators are often former athletes or coaches of the sport being broadcast.
Usage examples of "color commentator".
The Copelands tried hard to distract themselves, Drake with his guidebooks, his repositories of fun facts, assuming the role of color commentator on this trip, pleasure for him residing in the activity of seeing a thing, then reading about it, or reading, then glancing up to see what you have just read, the equation between word and object seemingly real and direct, knowledge was instantly practice, and vice versa.