You can’t say Mark Duper without saying Mark Clayton and you can’t say the Mark’s Brothers without saying Dan Marino.
Clayton left the NFL after a long career with the Dolphins but his ended with a trade to the Green Bay Packers. He left the league a year later.
Duper on the other hand spent his entire career with Miami. From 1982 to 1992, Duper was the deep threat receiver that Dan Marino looked for when he wasn’t looking at Clayton. They were a trio and should have all walked out together but that would have been the perfect fairy tale ending.
Instead, Duper opted to retire from the NFL after the 1992 season. He started all 16 games that year and posted 762 yards on 44 receptions. Neither the receptions, nor the yardage were the lowest of his career, nor the highest. He was still playing at a solid level and if he played in this era he would probably have added several years to his career.
In his final season, he posted seven touchdowns which was the most he had since an eight touchdown season in 1987. Duper for all he had done didn’t have to watch his legacy falter with another year or two trying to hang on. While you could say he didn’t go out on top, most don’t, you can say that he went out still playing at high level.