Saskatchewan MP Andrew Scheer will declare his candidacy for the leadership of the Conservative Party tomorrow.

The former Speaker of the House of Commons stepped down earlier this month from his role as Opposition House leader in order to get ready for his leadership bid.

He's called a press conference for 1:30 p.m. Wednesday in Ottawa, where campaign sources tell CBC News he will make his candidacy official.

Scheer is expected to have several MPs and senators behind him for his formal announcement.

It's unclear if he will file his paperwork and hand over his cash deposit tomorrow, but that's also expected to happen shortly.

Scheer, one of the few candidates in the race who is functionally bilingual, was born in Ottawa. But he has represented a Saskatchewan riding since 2004, defeating an New Democrat incumbent to take his Regina seat.

'Unifying figure'

Edmonton MP Garnett Genuis told CBC News earlier this month that he would welcome Scheer's candidacy and he sensed a lot of caucus support for his bid.

"Scheer is a unifying figure for different parts of the Conservative family," he said, contrasting that with a candidate like Kellie Leitch, who introduced the wedge issue of screening for "Canadian values" into the campaign.

Fellow Alberta MP Shannon Stubbs also said then she was excited that Scheer was running, because he is affable and likable and offers policy depth in tune with people's priorities.

She described him as a fiscal conservative who will bring people together.

For much of the Harper government's time in office, Scheer was first a deputy Speaker and then elected Speaker of the House of Commons in 2011. His experience as Speaker could be both an asset and a detraction as he takes on a more partisan role than he's held for the bulk of his parliamentary career.

Other candidates

Scheer's entry into the race will bring the official list of candidates to six.

He joins Maxime Bernier, Micheal Chong, Tony Clement, Kellie Leitch and Deepak Obhrai.

Two of the big names expected to enter the race a year ago both decided against it.

Peter MacKay has decided to stay in the private sector, while Jason Kenney is running for the leadership of Alberta's Progressive Conservative party.

The contenders, so far

Candidate who has declared, registered and paid the full fee: Michael Chong.

Candidates who have declared and registered: Maxime Bernier; Tony Clement; Kellie Leitch; Deepak Obhrai. (Andrew Scheer now joining this list.)

Potential candidates who have declared only: Dan Lindsay; Pierre Lemieux; Adrienne Snow; Brad Trost.

Expected to declare soon: Chris Alexander; Steven Blaney.

Others who have mused about running but not declared: Kevin O'Leary; Erin O'Toole; Rick Peterson; Lisa Raitt.