It will be very difficult for the Colts and Luck to secure a contract agreement before next week's draft, NFL Network insider Jason La Canfora reported.
The rookie pool numbers won't be known until after the draft, so allocating the exact contract figures and negotiating a contract would be "quite difficult," a source who would be involved in the process told La Canfora.
While the sides have a pretty good idea of what Luck will earn, given the realities of the rookie scale, actually finalizing a contract without knowledge of the entire scope of the rookie pool to sign all of the team's picks is unlikely, according to the source.
Colts general manager Ryan Grigson said Wednesday that the team had made up its mind as to whom it would take first in the draft, though he refused to tip his hand to the Indianapolis media.
"We've known for a little while. We've done all our due diligence," Grigson said Wednesday. "Unless there's an unforeseen problem or something like that, we know what we're doing."
The Colts brought Luck to Indianapolis for a private workout earlier this month, something they did not do with Baylor quarterback Robert Griffin III, who long has been the presumptive No. 2 overall pick by the Washington Redskins.
Luck threw for 3,517 yards and 37 touchdowns with 10 interceptions in leading Stanford to a trip to the Fiesta Bowl last season.