Simple. OL went really fast this year. Once we picked up Frederick the grades dropped off significantly. In the war room, at some point the question must have been asked "If we get this guy here, is he any better than Leary right now?" ( or Bern, Kowalski et,al)
Do we grab a guy or do we push on developing what we have. The guys on our roster now have a year under Callahan's system. It's not out of the question to expect SOME improvement at a postion or 2 along the line from our existing guys....especially with all the injuries we had that hurt continuity.
In addition, Jerry was pretty clear (as clear as he can be, I guess) that he believes in the idea that sub-par players can be hidden along the line. The key to "hiding" players is to put strong guys around them. The problem we had last year was that they ALL had problems at different times. Now that we can anchor the center position, that can make the guards better even if (god forbid) we roll out with Bern and Livings again.
I'm not sure what we do at RT at this point, but Parnell may be the front runner there. By the 3rd rnd of the draft, there was probably no one we felt was any better today than Parnell would be .