An email from her office late Thursday afternoon said a "special announcement" will be happening at 11 a.m. at her campaign headquarters in downtown Ottawa.
CBC News has learned she will officially announce her withdrawal from the leadership race.
MacLeod had been one of four candidates to replace Tim Hudak as leader of the provincial PC party, along with Christine Elliot, Patrick Brown and Monte McNaughton.
Ottawa city councillor Scott Moffatt took to Twitter on Thursday saying he and fellow councillor Jan Harder were urging MacLeod to run in the newly created federal riding of Nepean.
Ottawa West-Nepean MP John Baird, who announced he is leaving politics earlier this week, was originally slated as the federal candidate for the new Nepean riding.
MacLeod was first elected in the rural Nepean-Carleton provincial riding in 2006 and re-elected three more times. The new federal riding of Nepean closely mirrors her provincial riding.