When Wayne Rogers quit the Korean War war comedy shortly before Season 4 (stemming from his dissatisfaction with Capt. “Trapper” John McIntyre’s sidekick status), Mike Farrell seamlessly stepped in as Capt. B.J. Hunnicutt, who proved to be a perfect new still-sipping swamp-mate for Alan Alda’s Hawkeye.
(Weeks later, Harry Morgan would show up as Col. Potter to fill a void left by McLean Stevenson’s Col. Blake, in another of the series’ A+ succession plans.)