[ol]
[li]Has anyone kept track of which positions get traded the most?[/li][li]Is there a strong correlation between number of times a player is traded and success or longevity in the game?[/li][/ol]
I suspect that the answers are
[ol]
[li]Yes[/li][li]No[/li][/ol]
Trades aren’t that common in football. If you exclude the cases of players traded for a draft pick or other compensation, they’re relatively rare.
I’d go further and say that because of this, and because pro football careers tend to be substantially shorter than in other sports, there are very few players who have been traded more than once. It’s such a small sample size, and I’d wager that the only way a player can get traded more than once is to have along career.
As far as I know, there are no reference sources that have compiled a comprehensive list of NFL trades. That’s not the case for baseball, basketball, or hockey.