Indianapolis Colts GM says Andrew Luck's deal impacts ability to improve defense

Indianapolis Colts general manager Ryan Grigson blames part of the struggles on defense because of quarterback Andrew Luck's new $140 million contract.

Grigson said on Jay Mohr's radio show that the Colts can't spend as much money on defense as they would like.

"We have a defense that is work in progress," Grigson said Friday on the Fox Sports Radio show. "When you pay Andrew what we did, it's going to take some time to build on the other side of the ball."

Luck signed a contract extension with the Colts in June worth $140 million over six years through 2021, including an NFL-record $87 million in guaranteed money.

Through four games this season, the Colts rank 25th in yards allowed per game and 30th in points allowed per game.

The Colts have finished 20th or worse in defense in three of the four seasons Grigson has been general manager. All four of those years were while Luck was under his rookie contract.

The Colts have no players remaining from their 2013 draft and they waived cornerback D'Joun Smith, the team's third-round pick in 2015, last month.

"We have missed on picks, that's for sure, we have," Grigson said on Fox Sports Radio. "I have to do better in that respect."

The Colts are 1-3 heading into Sunday's game against the Chicago Bears (1-3).