Poplawski was originally a territorial exemption his hometown team the Edmonton Eskimos and prior to the beginning of the 1978 season he was traded to the Bombers in exchange for their star receiver Tom Scott. With 75 receptions for 998 yards and 8 touchdowns, Poplawski won the CFL's Most Outstanding Rookie Award in 1978. That season he was also selected to the Western Conference and CFL all-star team as a wide receiver. Despite a short career Poplawski achieved many more accolades including twice winning the Most Outstanding Canadian awards in 1981 and 1986. He was also the runner-up for this award in 1980, 1984 and 1985. He was selected to the All-Star team five times, first as mentioned above and four more times as a slotback in 1981, 1984, 1985, and 1986. Poplawski helped the Bombers win the 72nd Grey Cup in 1984 with five catches for 101 yards and a touchdown. At the age of 29, he ended career with 8,341 receiving yards on 549 receptions and with 48 touchdowns. In his final season, he temporarily filled in as the team's kicker, following an injury to Trevor Kennerd. Poplawski made 8 out of 10 field goals, totalling 233 yards, with his longest coming from 45 yards out.
After leaving football Poplawski pursued a career as a professional soccer player. Currently he heads up the Cavalier Drive branch of Ranger Insurance in Winnipeg, acquired in July 2014 by Arthur J. Gallagher Canada Limited. Poplawski also worked as an analyst for CJOB radio alongside play by play man Bob Irving.