Complex sentence: Louie Kelcher (born in 1953) whose heroics as a defensive tackle on the San Diego Chargers made him one of the teams most popular players from 1975-83.
Split into simpler sentences: Louie Kelcher (born in 1953), was an American football player who played most of his career with the San Diego Chargers. His outstanding play made him one of the teams most popular players from 1975-83.