Dunlop was first elected in 1999 to represent the riding, a long-time Conservative stronghold just north of Barrie, but
announced today that he was stepping down.
The move comes as a bit of a surprise because Dunlop was one of the most vocal opponents to Brown in the PC caucus during the leadership race.
Brown resigned his Barrie seat in the House of Commons after winning the PC leadership in June, and said at the time he was not in a rush to find a riding in which he could run.
Premier Kathleen Wynne had said she'd quickly call a byelection when Brown found a riding in which he would run, but today she only said "stay tuned" when asked when voters in Simcoe North would be going to the polls.
Some Tories were worried Brown could face the same problems getting a seat in the legislature that former PC leader John Tory had after he lost to Wynne in a Toronto riding in 2007 and then lost a byelection in Peterborough.