"Can't say unequivocally that Luck will play in the Sept. 10 opener, but he'll be ready around the start of the season," said Irsay, according to the Indianapolis Star's Zak Keefer.
Irsay added that Luck has resumed throwing, according to Keefer.
"I would say his progression could not be better," said Irsay, according to Keefer.
Irsay said Luck is not yet throwing at full strength, as the team is waiting for the team doctors to sign off, according to George Bremer of The Herald Bulletin.
With Luck ailing and journeyman Scott Tolzien atop the depth chart, Indy was expected to consider bringing in another arm. Irsay confirmed the Colts discussed signing a veteran free agent, but said they were ultimately turned off by the high price, according to Bremer.
While it appears Luck's Week 1 status remains in doubt, Irsay's update is the biggest reason for optimism yet.
Colts general manager Chris Ballard also commented on Luck's rehab Sunday, saying the pivot was stronger now than at any point last season.