Sullivan has scheduled a morning news conference at a Vancouver hotel where he is expected to announce efforts to win the Liberal nomination in Vancouver-False Creek for the May election.
The expected declaration comes on the same day longtime B.C. Civil Liberties executive director David Eby has announced he's set to challenge the premier again in her Vancouver riding.
Eby confirmed on Twitter Friday morning he's been acclaimed as the NDP candidate in Vancouver-Point Grey. Last May, he lost the by-election that gave the premier her seat by only 600 votes.
Sullivan, however, may have to fight to win his nomination.
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Lorne Mayencourt, a former Liberal MLA and federal Conservative Party candidate, said he's considering a run for the nomination in the same riding and will make a decision within the next two weeks.
The largely downtown Vancouver riding is currently held by former Liberal children's minister Mary McNeil, who announced she was retiring from provincial politics after serving one term in Victoria.
Mayencourt said he doesn't see his potential candidacy in the riding as a personal challenge to Sullivan, but a reflection of the strength of candidates willing to run for the Liberals in the spring election.
Mayencourt is currently working with Premier Christy Clark's Liberal government as the caucus outreach director, but he said trying to get back into elected office is tempting.
Sullivan, 53, is no stranger to nomination battles, defeating Clark in 2005 for the nomination to seek the Vancouver mayor's job under the Non-Partisan Association banner. Sullivan lost the NPA's nomination in 2008.
The most prominent and endearing image of Sullivan, a quadriplegic as a result of a skiing accident when he was 19, is of him waving the Olympic flag from his wheelchair during the closing ceremonies of the 2006 Winter Olympics in Turin, Italy.
Sullivan said he received thousands of letters from people around the world inspired by his flag waving.
Sullivan is also known for his long history with British Columbia's Chinese community, speaking both Cantonese and Mandarin.
Before he was mayor, Sullivan became embroiled in Vancouver's ongoing struggles with street crime and drug abuse.
Sullivan told the RCMP he gave $40 a day to a 20-year-old woman working as a prostitute in his neighbourhood. He said he knew the money would go to buy drugs, but he believed drug addiction was a disability and he was attempting to develop city programs to reduce crime and addiction.
Sullivan also said he gave money to a crack addict and allowed him to smoke drugs in his van. He said his van was a safe place and said he'd rather give the man money than let him steal from others to supply his habit.
In 2008, Sullivan lost the NPA nomination race to Peter Ladner, who ran for mayor but lost to current Vancouver mayor Gregor Robertson.
Sullivan formed the Global Civic Policy Society when he left politics. The organization aims to encourage community building in urban environments.