Ken Coran is roffiically etiring on June 30.
On Friday the Liberals said he will be the unopposed Liberal candidate in the riding of London West.
Coran's candidacy provoked wonder from the Progressive Conservatives who said it wasn't that long ago he was calling for the downfall of the Liberals.
"He actually stood outside the Liberal leadership convention saying this was a corrupt government," said MPP Rod Jackson.
"In fact, he wrote a confidential memo to the OSSTF stating that he was responsible for bringing Premier McGuinty down and causing all these resignations within the government," Jackson said. "Now he's one of their candidates? Pretty rich."
But Coran says he's running because he's a supporter of Premier Kathleen Wynne.
A total of five Liberal seats are now up for grabs, including for finance minister Dwight Duncan's spot in Windsor.
The former finance minister says the exodus is not a slight to Wynne.
"It was important when Premier McGuinty retired for some of us around him to go too, so the new leader could put on her own government," Duncan said.
The dates for the byelections have not been set.