The Black Cats have been forced to consider other options to replace David Moyes after Aberdeen boss Derek McInnes turned them down yesterday as he instead chose to remain in the Scottish Premiership.
Grayson has since emerged as one of the new frontrunners to land the role, but the 47-year-old played down the possibility of making the move to the Stadium of Light.
"As far as I'm concerned there's a lot of speculation about a lot of different jobs, but I'm fully committed to working out what we're doing for the season at Preston," he told talkSPORT.
"I don't consider it [the speculation] whatsoever until someone says something different, whether it's Sunderland or any other job. We've had a good couple of years in the Championship [at Preston] and we want to keep improving. We were on the periphery of the playoffs last season and just ran out of steam in the back end of the season.
"I've been there just over four years now and really enjoyed my time. You just get on and do what you do and I'm focused on trying to get things right at Preston. I'm fully committed to Preston and, if anything changes along the way, that's just football."
Grayson has been in charge at Deepdale since 2013, leading the club into the Championship from League One.