Foreign Affairs Minister John Baird will resign from his position in the Harper cabinet as early as Tuesday, CBC News has learned.

Sources say that Baird, who has served in several senior portfolios in Prime Minister Stephen Harper's cabinet, has told members of his staff that he won't run again and will be resigning this week.

In a statement late Monday, spokesman Rick Roth said Baird would make "an announcement" in the House of Commons Tuesday at 10 a.m. ET.

International Trade Minister Ed Fast will be named acting foreign affairs minister, sources tell CBC News.

Baird's departure from cabinet, along with the resignation of Jim Flaherty a month before his death last year, means two of Harper's most powerful ministers will have left the prime minister's inner circle in less than a year.

As foreign affairs minister, Baird has overseen a busy file, handling Canada's diplomatic response to the war in Libya, the crisis in Ukraine, the Palestinian push for statehood, the coalition mission in Iraq and most recently, the case of jailed Canadian-Egyptian journalist Mohamed Fahmy.

Baird represents the riding of Ottawa West-Nepean and was nominated last March as the Conservative candidate in the newly created riding of Nepean for the next federal election, which must be held by Oct. 19 at the latest.

Baird, 45, has been in politics most of his adult life. He was first elected as an MP in 2006 after a decade in provincial politics in Ontario, where he served in former premier Mike Harris's cabinet.

However, sources close to Baird say that after 20 years in public office, it was simply time to seek other opportunities. His experience and profile are expected make him attractive to the private sector.

A source close to Baird said he still supports the prime minister and will campaign for the party in the election.

High-profile posts

One of Baird's first jobs after the election of the Harper government in 2006 was to get the Conservatives' Accountability Act passed. His cabinet roles have included:

Minister of Foreign Affairs, May, 2011 to present.

Government House Leader, August, 2010 to May, 2011.

Minister of Transport, Infrastructure and Communities, October, 2008 to August, 2010.

Minister of the Environment, January, 2007 to October, 2008 and again November, 2010 to January, 2011.

President of the Treasury Board, February, 2006 to January 2007.

Baird was also a member of the House of Commons' Board of Internal Economy in 2010 and 2011.