He had his best season in 1984 when he had 71 catches for 1306 yards and eight touchdowns and in 1986 where he pulled in 67 catches for 11 touchdowns. Super Duper had four 1,000 yard seasons. In 1988 Duper was suspended by the NFL for 30 days for being in violation of its drug policy. After retiring in 1993, Duper was charged with conspiracy and intent to distribute cocaine. He was acquitted one year later. In March 2013, Duper was charged for beating his 17-year old son at their home in Jacksonville, Florida. Duper revealed that he has been diagnosed with chronic traumatic encephalopathy (CTE) in November 2013. Mark Duper (alongside Mark Clayton) was inducted into the Miami Dolphins Honor Roll in 2003.