9. QB Mark Malone, 1980 (#28)
There are several quarterbacks the Steelers drafted to replace Terry Bradshaw, who could have made this list. But unlike some of the others, Mark Malone was drafted in the first round, and he still had plenty of talent around him. Malone appeared sparingly during his first three seasons with the team but finally got his chance in 1984.
After appearing in a few games sparingly and handing the eventual Super Bowl Champion San Francisco 49ers their only loss of the season, he seized the starting job in Week 9. He led the Steelers to the AFC North title and the AFC Championship, where they lost to Dan Marino and the Miami Dolphins.
Unfortunately, it was all downhill for Malone after that. He never finished a season with a winning record as a starter and never finished a season with a completion percentage higher than 51%. He also struggled to stay healthy, never playing or starting more than 14 games in a season. Malone was traded to the San Diego Chargers in 1988 and finished his career with the New York Jets before retiring in 1989.
Overall, the 1980 NFL Draft was not particularly loaded with talent, especially at the quarterback position. Only three Hall of Famers came out of this draft, with only one being available for the Steelers to pick at #28 (C Dwight Stephenson, Miami Dolphins). Furthermore, only nine players made First-Team All-Pro from this draft, one of whom was a kicker, and four others were available for Pittsburgh to select in the first round.
So it’s not like there was an obvious choice for the Steelers to select instead of Malone, but his struggles prevented Pittsburgh from extending their dynasty into the 1980s.