Say the name Bobby Thomson and before long someone is sure to bring up his 1951 partner in baseball history, Ralph Branca. Ever since the 1986 World Series, Mookie Wilson and Bill Buckner have gone together like a hot dog and a beer (or perhaps more like oil and water, if you’re a still-mournful Boston Red Sox fan). Mark McGwire and Sammy Sosa are forever joined in grace by their 1998 pursuit of a home-run record, and in disgrace by their reliance on performance-enhancing drugs. And what figure-skating fan can hear about Nancy Kerrigan without thinking of Tonya Harding, the two being linked by a bizarre episode of attempted kneecapping in 1994?

In much the same way, any conversation about football that mentions the splendid Peyton Manning is bound at some point to turn to his onetime doppelgänger, Ryan Leaf. In 1998, Messrs. Manning and Leaf were blisteringly hot prospects as they entered the National Football League’s annual draft — college quarterbacks of exceptional promise, either of them certain to be that year’s No. 1 pick. As recalled in the latest weekly video documentary from Retro Report, that was exactly how the 1998 draft played out. Mr. Manning was selected first, by the Indianapolis Colts. Mr. Leaf was chosen next, by the San Diego Chargers.

That is where similarities between the two men dissolve. Peyton Manning went on to become one of the best pro quarterbacks of all time, capturing five most valuable player awards and leading teammates to three Super Bowls. Ryan Leaf? For all his physical prowess and an $11.25 million signing bonus, he became a synonym for an absolute bust. He played in a mere 25 games across four seasons. His passes resulted in many more interceptions than touchdowns. After football, his life skidded off the road. He had a pill problem. In 2012, he began serving a seven-year sentence in his native Montana for breaking into a house in search of painkillers.

So, with the 2014 pro football draft upon us this week, does it boil down to a matter of character?

The Colts seemed to think so. In Mr. Manning, a member of a family that qualifies as pro football aristocracy, the team believed it had a master of control and poise. Mr. Leaf was the stronger athlete in many respects, but he turned out to have a 10-cent emotional quotient to go with his million-dollar arm. He was hot-tempered and at times lackadaisical in his training habits. The focus on character — “intangibles” being a favored word — is reflected in a current movie, “Draft Day,” with Kevin Costner playing a football team’s general manager who is more concerned with a prospect’s inner qualities than with his throwing arm.