In 1970, he coached the minor-league Texarkana Titans of the Texas Football League, leading them to a 7-3 record and a playoff appearance.
Merrill was behind the plate in Game 2 of the 1983 ALCS when Mike Boddicker tied an LCS record with 14 strikeouts, and Game 2 of the 1988 World Series, when Orel Hershiser of the Los Angeles Dodgers fired a three-hit, 6–0 shutout vs. the Oakland Athletics, led by "Bash Brothers" Jose Canseco and Mark McGwire.
Merrill amassed a large memorabilia collection consisting of signed baseballs, game used jerseys and bats from MLB players.
Merrill suffered a heart attack in early January 2003, and died a few days later in Texarkana, Texas, at age 64.
His family sued several doctors, nurses and Christus St. Michael Health Care Center after his death, alleging medical malpractice.