Ontario deputy premier George Smitherman will resign from cabinet on Monday to prepare his run for mayor of Toronto in 2010.

Premier Dalton McGuinty confirmed Sunday night that Smitherman would step down from his posts, which also include energy and infrastructure minister.

"He will be staying on as the MPP for Toronto Centre for a short time while he finishes several projects in his community," McGuinty said in a statement.

"Since he was first elected to the provincial legislature in 1999, George has helped make Ontario a better and stronger place," he said.

Veteran Liberal MPP Gerry Phillips, currently a minister without portfolio, will replace Smitherman as head of the energy and infrastructure ministries in the short term, according to The Canadian Press.

After months of denying he was eyeing the mayor's job, Smitherman gave a strong signal in September that he was considering making a bid.

Smitherman's entry into the race would set the stage for a possible showdown between two political foes who once battled it out at the provincial level.

Former Progressive Conservative leader John Tory has made it clear he hasn't ruled out a run for mayor in 2010.

Tory was defeated by current Mayor David Miller in 2003. Miller announced in late September that he would not seek a third term.