Rep. Thaddeus McCotter (R-Mich.) is at risk of losing his place on the Aug. 7 primary ballot because of problems with his petition signatures, wreaking havoc on the GOP’s once-secure hold on his seat.

In a Friday statement, McCotter announced the secretary of state had questioned whether he collected sufficient signatures to make the ballot.

“I have been apprised my campaign may have submitted insufficient petition signatures to appear on the August primary ballot as a candidate for the 11th Congressional District’s Republican nomination,” he said in the late-night statement.

If the five-term Congressman gets booted from the ballot, Republicans will be forced to nominate a perennial candidate or mount a challenging write-in campaign for McCotter or another candidate.

McCotter filed 2,000 signatures to run for GOP nomination in the 11th district. But an initial review by the secretary of state’s office showed he had fewer than the 1,000 necessary to make the ballot, a spokeswoman told MIRS news, a Michigan political news service.

The elections board will certify signatures in early June, and McCotter will reportedly have the opportunity to make his case to stay on the ballot at that time.

Democrats previously touted Dr. Syed Taj as their candidate to challenge McCotter, but the race was not considered competitive. That could quickly change if McCotter is off the ballot and Republicans cannot write-in a strong replacement.