Michigan state Sen. Mallory McMorrow has suspended her campaign for the U.S. Senate, according to a campaign announcement released Tuesday. Her withdrawal leaves state Rep. Haley Stevens and physician and activist Abdul El-Sayed as the remaining major candidates in the Democratic primary.

The primary election is scheduled for August 4. McMorrow had been considered a contender in the race to succeed retiring Democratic Sen. Debbie Stabenow. Her campaign did not immediately provide further details on the reasons for her withdrawal.