AV Differential: 140

In February of 1999, the Washington Redskins saw something in Minnesota Vikings backup quarterback Brad Johnson, so they decided to package a deal (a first rounder and third rounder in that year's upcoming draft) for the 31-year-old, who they expected to become the team's starter.

The following year, Johnson started all 16 games and the Redskins went 10-6. He threw for over 4,000 yards and 24 touchdowns as he enjoyed the best season of his 15-year career. Mission accomplished, right?

Based on that one year, yes. However, it took just one more season for the tables to turn.

That first round pick became quarterback Daunte Culpepper, who -- after one year behind Jeff George and Randall Cunningham -- stepped in to start 16 games and throw for just short of 4,000 yards at the age of 23. His 33 touchdowns led the entire NFL, and he made his first of three trips to the Pro Bowl. After all was said and done, Culpepper threw for 135 scores across seven seasons in Minnesota.

You might also recognize the third round pick in the transaction: Joey Porter. Mr. Porter played 13 seasons in the league as an outside linebacker, producing an AV of 111 with one All-Pro season and four Pro Bowl appearances. But you don't know about his Vikings career because he never had one. Porter was subsequently traded to the Pittsburgh Steelers, the team he'd help win a Super Bowl in 2005.

Even for a moderately successful quarterback like Johnson, Porter and Culpepper are just too much to stack up against.