Jean says in a statement that his scheduled events for the next few days will go ahead with Derek Fildebrandt stepping in for him.
Fildebrandt is seeking to win the legislature seat of Strathmore-Brooks for the Wildrose in the next election.
Jean is a former northern Alberta Conservative MP.
He is running against Wildrose MLA Drew Barnes and former Strathcona County mayor Linda Osinchuk (OH'-sihn-chuk).
About 24,000 Wildrose members began voting on Monday and a new leader to replace Danielle Smith is to be announced March 28.
Smith, along with eight other Wildrose legislature members, crossed the floor in December to sit with the Progressive Conservative government.
Wildrose interim leader Heather Forsyth is not seeking re-election when Albertans next go the polls.
There is heavy speculation Premier Jim Prentice will call a provincial vote soon.