Dr. Eric Hoskins, who represents the Toronto riding of St. Paul's, resigned late Thursday as minister of children and youth services — a prerequisite for making a leadership bid.
Charles Sousa also quit as minister of citizenship and immigration and the minister responsible for the 2015 Pan and Parapan American Games on Friday.
Neither confirmed that they were running to succeed Premier Dalton McGuinty, but both hinted at it, saying they want to be a part of the party's renewal.
Sousa is expected to throw his hat in the ring Saturday when he makes a yet-unspecified announcement in Mississauga.
Hoskins, 51, said he'll be releasing more details on his decision at a news conference early next week.
"Together, I am confident that we can move our party forward with a strong, compassionate leadership rooted in principled politics," he said in a statement.
The Oxford-educated Rhodes scholar is perhaps more well-known outside political circles as a celebrated humanitarian who started War Child Canada with his wife, Dr. Samantha Nutt. They have a 7-year-old son, Rhys.
Hoskins is also an Officer of the Order of Canada and received the United Nations Lester B. Pearson Peace Medal, as well as the Governor General's Meritorious Service Cross.
He was first elected in a 2009 byelection that was triggered when former attorney general Michael Bryant left politics, and was soon elevated to cabinet as minister of citizenship and immigration. He was moved to the children and youth portfolio after the October 2011 election.
Sousa, who represents Mississauga South, was first elected in 2007 and has also served as minister of labour.
Before jumping into politics, Sousa worked at the Royal Bank of Canada Financial Group for more than 20 years, according to his MPP website. Before that, he owned and operated a factoring company that offered financial services to small businesses.
Sousa, 54, and his wife Zenny have three children.
"As we embark in our party's renewal process, I hope to continue to serve Ontarians in the spirit of passion and integrity the premier has exemplified during his time in office," he said in a statement.
Three other former cabinet ministers launched their leadership campaigns this week.
Sandra Pupatello, who left politics a year ago, as well as Kathleen Wynne and Glen Murray — both Toronto MPPs — have jumped into the race.
Gerard Kennedy, who lost to McGuinty in the 1996 leadership race by just 140 votes, said he hasn't made a decision yet.
A source says John Wilkinson, the former revenue and environment minister who lost his seat in last year's election, is still considering a bid.
The Liberals insist the race won't be divisive, but there are already signs that the claws are coming out.
Murray said he wouldn't wait to bring the legislature back if he becomes premier — unlike Pupatello, who said she won't bring the house back until she wins a seat.
He said he'd re-open parliament on Feb. 19, 2013, when the legislature was initially scheduled to return.
"We'll be ready if the opposition forces an unwanted election — at the same time, there's work to be done and it's better to try and make minority government work," Murray said Friday in a statement.
McGuinty has taken a lot of heat for shutting down the legislature Oct. 15 when he announced he would step down as premier, and some Liberals appear to be distancing themselves from a decision that critics say was politically motivated.
Proroguing the legislature killed planned committee hearings into the costly cancellation of two gas plants, as well as a rare contempt motion against embattled Energy Minister Chris Bentley.
McGuinty must now deal with running the province with a rapidly shrinking cabinet as more ministers launch their leadership bids.
Tourism, Culture and Sport Minister Michael Chan will be tasked with the citizenship and immigration file, as well as the 2015 Pan Am Games.
Education Minister Laurel Broten, who already has her hands full with angry teachers threatening strike action, will be taking on children and youth services in addition to her current women's issues file.
Potential candidates have until Nov. 23 to launch their bids. The party will choose McGuinty's successor the weekend of Jan. 25, 2013, in Toronto.
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