In March, Tom Brady left New England as a free agent to replace Jameis Winston, once the first pick in the draft, as Tampa Bay's starting quarterback.
Three years ago, Patrick Mahomes replaced Alex Smith, once the first pick in the draft, as Kansas City's starter.
On Sunday, Brady and Mahomes will face each other in the Super Bowl, proof that freedom of quarterback movement can be fascinating and fruitful.
Vikings fans know this. Their best two Vikings teams of the past 44 years were led by older quarterbacks who previously starred for NFC rivals — Randall Cunningham and Brett Favre. And the Vikings' glory years occurred after they traded to get Fran Tarkenton back from the New York Giants.
This year, the most intriguing story lines of the young NFL offseason involve one blockbuster quarterback trade — the Rams and Lions exchanging starters — and a slew that could happen.
Carson Wentz and Deshaun Watson want to move. The Cowboys don't seem to know what to do with their franchise quarterback. The 49ers, Saints, Panthers, Washington, Bears, Colts, Patriots, Dolphins, Jets, Jaguars and Broncos are or may be looking for a new starter. ESPN reporter Adam Schefter has speculated that 18 or more teams could have new starting quarterbacks next season.
Brady, Mahomes, Cunningham and Favre are four good reasons why the NFL needs to alter the way it manages its salary cap.
The cap in itself is a good thing. It rewards intelligent management and prevents larger-market teams from dominating the sport.