Victoria-Swan Lake MLA Rob Fleming announced he will not be running.
Fleming, who serves as the party's education critic, was one of at least seven candidates who were expected to join the leadership race.
So far former NDP house leader John Horgan and Mike Farnworth, who finished second to current leader Adrian Dix in the 2011 leadership contest, are the only two contenders for the party's leadership.
The NDP will be selecting Dix's replacement in September.
The bid to replace Dix comes after he lead last year's unsuccessful election campaign where the incumbent BC Liberals defeated the NDP in a shocking upset despite the opposition party's initial 20-point lead in the polls.