Contract negotiations are always tricky situations to work through. The player wants more money than the team is willing to give because he's putting his career on the line every time he steps on the field of play.
Lets look at the case of Tom Brady. Here is a guy that it could be said is underpaid in relation to the success that he has helped to bring to New England. When you consider that Brady steered the Patriots to 4 Super Bowls, won 3 of those, and led the team to the first undefeated regular season since the 1972 Dolphins.
Peyton Manning is getting paid a lot more than Brady, but has only led his team to the Super Bowl once, which the Colts won.
Bottom line: Brady has proven himself above and beyond the $6.5 million he is scheduled to make this year. The dude needs to get paid.
No rational person would say that Sam Bradford should get up to $50 million guaranteed when he has had none of the NFL success that Brady has had up to this point.
Mr. Kraft, pay the man what he is due.