Irsay is currently out of action for the Colts having been charged with four felony counts of possession of a controlled substance following his arrest on suspicion of intoxicated driving last week.
He has since entered a healthcare facility to deal with his problems, but Grigson does not believe that it will have an adverse effect on his side's dealings.
"When there's big dollars, something major going on, Jim is always right there, but he leaves the football decisions up to me and he trusts me. He hired me to make football decisions, so I don't see any of that changing," Grigson is quoted as saying by ESPN.
"If there's something I need to lean on him about in terms of using his football knowledge for my benefit, for the Colts' benefit, I reach out to him, but like I said, he doesn't micromanage me; he lets us all do our job. I don't really see it being an issue."
Grigson also refused to rule out making further moves in the free agency market but insisted that he was happy with the business that they have done so far.
"You never say you're done, but if something pops up I'm always looking at it. If one of my guys brings me a name that is of interest, I'll look at him," he added.
"We had a plan in place and we feel really good about it and we feel real good where we're at right now."
Grigson also gave his backing to Irsay and expressed his desire to see the 54-year-old make a full recovery.