Complex sentence: After a mediocre 1975 season the Bills had internal troubles in 1976, as the team dropped to the bottom of the AFC East, where they stayed for the rest of the 1970s.
Split into simpler sentences: After a mediocre 1975 season, the Bills had internal troubles in 1976. The team that year, dropped to the bottom of the AFC East, where they stayed for the rest of the 1970s.