Note: this piece does not mean I expect Moss to come to Indianapolis. I don't expect that (barring injuries to Indy WRs), and don't want that. This is strictly an academic exercise.
In a recent discussion about Randy Moss, I called him "a quarterback maker". A reader in the comments challenged that notion, so I've done the research to back up the claim. For the sake of simplicity, I'm mostly relying on passer rating as a shortcut to understanding Moss's effect on the offense. I'm only including quarterbacks who played at least 8 games with Moss.
Here is a brief history of Randy Moss's career:
1998-99: Randall Cunningham
With Randy Moss, Cunningham's passer rating was 97.4
For the rest of his career, his passer rating was 78.8.
1998 was Cunningham's best season.
Moss effect: +18.6
Note: Cunningham played in the same Vikings offense without Moss in 1997 and posted a rating of 71.3 in limited duty.
1999: Jeff George
With Randy Moss, George posted a rating of 94.2
Without Moss, George's career rating was 79.1
1999 was George's best season.
Moss effect: +15.1
1999-2004: Dante Culpepper
With Randy Moss, Culpepper's rating was 92.8
Without Randy Moss, Culpepper's rating was 76.3
Moss effect: +16.5
Additionally, it has been pointed out that Culpepper's best season was 2004, a year when Moss was injured. This is true, but Moss still played 13 games (really 11) and caught 13 touchdowns. Culpepper's rating in the five games where Moss didn't play or played a few snaps without catching a pass was 98.9. His rating in the other 11 games with Moss was 116.2.
Culpepper's only good years were with Moss.
2005: Kerry Collins
With Randy Moss, Collins posted a rating of 77.3
For the rest of his career, Collins posted a rating of 73.5
Moss effect: +4.8
Collins played the previous season in Oakland without Moss and posted a rating of 74.8
Moss was hurt and played just 13 games, not reaching 8 games with either quarterback. The two combined for just 8 more throws in one more NFL game after 2006.
2007-2010: Tom Brady
With Randy Moss, Brady's rating was 107.0
Without Randy Moss, Brady's rating was 91.0
Moss effect: +16.0
In 2010, Brady played 4 games with Moss and posted a rating of 109.0. In his 12 games without Moss his rating was 111.6. Brady's 3 best seasons all came with Randy Moss.
2008: Matt Cassel
With Moss, his rating was 89.4
Without Moss, his career rating is 80.5
2008 was his second best year.
Moss effect: +8.9
Moss has played with quarterbacks at every phase of their careers. Cunningham (36), George (32) and Collins (33) were all past their primes. Culpepper and Cassel were young players who had not yet reached their primes and were just learning. Tom Brady was in his prime.
Combined, a quarterback who played with Moss for at least 8 games posted a rating of 94.2. To put that in perspective, that's roughly Peyton Manning's career rating. Those same quarterbacks playing without Moss posted a rating of 79.6 over the rest of their combined careers.
Moss may not have been the only reason for his quarterback's success, but there is a clear and distinct pattern of Moss elevating the play of the quarterbacks he played with. He did it with old, young, and in their prime quarterbacks. He did it with runners and pocket passers. He did it with Hall of Famers, Pro Bowlers, and journey men. The only quarterback who showed no improvement with Moss was Aaron Brooks who was so often injured and so bad that he never played another down in the NFL after that season. Even he only played 7 games with Moss.
Denying Randy Moss the title of "Quarterback Maker" is to deny the numbers.