I think Greg Jennings' contract could be modeled after the one signed by Anquan Boldin in 2010 with the Baltimore Ravens. And not only was that contract reasonable, one could easily argue in the negotiations process that Jennings should be paid less.
1. Anquan Boldin was going to turn 30 years old in the upcoming NFL season, just like Greg Jennings. They were both 29, going on 30. In this, the two are similar.
2. There's an argument that Greg Jennings has been made by the QBs throwing to him. Similarly, there was an argument that Anquan Boldin's downslope was being masked by the fact that he had Larry Fitzgerald opposite him and Larry drew all the defenses' attention. Boldin also had a pretty durn good quarterback throwing to him in Kurt Warner.
3. Anquan Boldin's contract was 4 years, $29 million with $10 million guaranteed. That included a $6.125 million signing bonus, a $2.875 first year roster bonus, and another $1 million in guarantees elsewhere in the deal. The average was $7.25 million per year.
4. Career-wise, the two were similar. Greg Jennings has 425 catches for 6537 yards and 53 touchdowns in 96 games. To that point in his career, Boldin had 586 catches for 7520 yards and 44 TDs in 95 games. Very similar, IMO...as the 1,000 extra yards balance against the 9 extra TDs.
5. However, Anquan Boldin was not coming off an injured year, unlike Jennings. Boldin caught 84 balls for 1024 yards and 4 TDs in 2009. Jennings only caught 46 balls for 481 yards and 5 TDs in 10 games of 2012, counting playoffs. Boldin also caught 103 balls for 1228 yards and 12 TDs in 15 games en route to a Super Bowl appearance in 2008. Jennings only caught 71 balls for 989 yards and 9 TDs in 14 games counting the playoffs in 2011. All in all, that's 187 catches for 2252 yards and 16 TDs in the two seasons immediately preceding the new contract for Anquan Boldin, versus 117 catches for 1470 yards and 14 TDs for Greg Jennings. That's a pretty big factor.
6. Should there be an inflation premium? Tough to say. The 2009 salary cap was $123 million. The 2010 season was uncapped, but most teams treated it like a capped year and the ones that did not were severely punished by Roger Goodell. When the salary cap was reinstituted in 2011, it was set to $120 million. There it remained in 2012, and it would appear it shall remain there in 2013 as well. If you're an NFL team you may even be able to argue that 2010 contracts are incomparable to 2013 contracts on the basis of there being no cap in 2010. That argument might not go over well, but the fact remains that because the NFLPA essentially "borrowed" in order to keep the 2011 salary cap at $120 million (should've been $116 million, just going off revenues) and to keep the 2012 cap at $120.6 million (should've been $113 million)...it means the 2014 salary cap is not actually going to go up much. The NFL projects that 2014 and 2015 salary caps should only be around $121-122 million. This means that contracts signed from 2009 to 2012 should be perfectly comparable to contracts negotiated in 2013...no inflation adjustment.
Given all this there's actually a good chance that Greg Jennings' contract negotiations would come down to a price point that is similar to what Brian Hartline is currently asking. Brian Hartline wants 5 years, $33 million. That could actually be Greg Jennings' price point, except the deal would likely be shorter, around the same Boldin signed.
If you're asking me whether I would take Greg Jennings or Brian Hartline at the same price...the answer is easy to me. And I don't think the Ravens regret giving Boldin that 4 year, $25 million deal.
I've never seen Brian Hartline do this:
http://www.youtube.com/watch?feature=player_detailpage&v=osxixxurzvk#t=279s