As I have the cable channel "Willow", I notice that when they piggyback off of Channel Nine, Sky, SuperSport or the like for test cricket matches, and sometimes even One-Day International matches, that the broadcasters in the play-by-play and color commentary positions are switched out every 20 to 30 minutes. Cricket is the only sport I've really seen this for. The closest I can think of this happening in the U.S. is when an aging announcer (the great Vin Scully for example) calls the first three innings, takes the middle three innings off and comes back for the 7th, 8th, and 9th (plus extras if they happen). Do any other sports have the people calling the action take shifts like they are ice hockey players?