Nicolas Constalonto - "Coach" from Cheers - that's when Woody Boyd emerged onto the scene. Around the end of the 3rd Season, Nicolas found that he only had so long to live from an illness. The cast knew he had 3 months or a year. Sadly, it was the 3 months. He filmed his last episode "Cherrio Cheers" and later died before the season ended. Throughout the rest of the season, the writers still had "Coach" in the series - acting like he was away on vacation and they even used bloopers in the episodes to make it look like he was still there. Then at the beginning of the 4th Season, they revealed that he had died after they did that "flashfoward" thing...Very sad - i hated to see him go ... such a great character for such a strong and irresistable series.
Rest in peace Nicolas..
Also, Edith Bunker played by Jean Stapelton was written out of the series and her character was killed off...Although she didn't die in real life...but it was really sad to see that character die...It was on the spin-off from "All in the Family" to "Archie Bunker's Place"...Jean was rarely on the series on account she was busy on Broadway. She talked with the writer's and said she didn't want to do the show anymore and they wanted to know if it was okay that they killed Edith off. She was worried but the Norman Lear said to her softly, "She's just a character..." It was tough though on account of the death of vital character...