I think you need to figure out what most other NFL teams hold back for injuries and do that, and I guarantee we held back more than they did because we had more caproom than most NFL teams.
People have to remember in the offseason the rumors were we were actively interested in either Alexander or Edge, and the asking price was a 2nd round pick, and we balked. That pick became JJ, who I think will be a good player but certainly wasn't NFL ready. Can't for one minute believe the Cards felt the 44th pick in the draft was going to be better than Edge or Alexander so they had to say no because of the contract they'd have to give them.
Later in the offseason word break we were one of the teams looking at Patrick Surtain, I got all excited since I'd been hyping that for weeks because it would mean we didn't HAVE to take a CB with the first pick if a better player fell to us. Again the asking price was not high, the Chiefs gave up their 2nd and 5th rounder to Miami in exchange for Surtain and the Dolphins 5th round pick. THe Chiefs moved UP in the 5th round in the deal so essentially Surtain was traded for a 2nd rounder. Again the reason the Cards weren't interested? Because Surtain got a 7 year deal for a lot of money the assumption is the Cards balked at the contract he wanted.
In either situation you can easily argue that giving up the 2nd rounder would have helped the team this year, even with Surtain now injured the Chiefs got more games out of him than we did rolle(and he's not out for the year) and we STILL could have taken Rolle at 8 if Green really felt he was the BPA. Or we could have taken Derrick Johnson, moved down and taken Aaron Rodgers, take Jammal Brown(OT went to the Saints) etc. There was no clear cut can't miss DT in this draft, Travis Johnson went the highest but he's the same size as Dockett and not as good a player.
The point is in both cases it would appear the Cards felt the contract for the player was going to be too high to justify giving up the 2nd round pick, so money made the decision. If money didn't make the decision then we have to believe that Rod Graves and Dennis Green believed the 44th pick in the draft was better than Edge, Alexander or Surtain.