Steven Del Duca, a longtime resident in the riding, was nominated as the candidate Sunday afternoon.
Del Duca is the director of public affairs for the Carpenters District Council of Ontario, and has been active as a community advocate.
The seat became vacant when Sorbara resigned earlier this month.
There is also a byelection the same day, Sept. 6, in the riding of Kitchener-Waterloo.
It became vacant after Progressive Conservative Elizabeth Witmer resigned to become chairwoman of the Workplace Health and Insurance Board.