June 3 (UPI) -- James Craig, once the front-runner in the GOP primary race for governor of Michigan, lost a court challenge to appear on the Aug. 2 ballot after the Board of State Canvassers determined his campaign petition did not have enough valid signatures.

The Michigan Court of Claims on Thursday denied an appeal from Craig's campaign following his removal from the ballot by Michigan's Bureau of Elections.

He is one of five candidates the Board of Canvassers didn't certify, cutting the field of candidates in half. The Bureau of Elections determined that many petition signatures for their campaigns were fraudulent and invalid, leaving them short of the 15,000-signature threshold.

The Michigan Court of Appeals denied appeals by candidates Perry Johnson and Michael Markey. Donna Brandenburg filed a legal challenge Thursday. Mike Brown withdrew from the race. Friday is the deadline to certify August primary candidates in Michigan.

Michigan GOP candidate won't quit race after false signature accusations