Joe O’Dea is the only candidate vying for the GOP Senate primary election to go the petition route this cycle, all others will face off during the party’s state assembly on April 9.

The Denver construction company owner filed his petition with more than 23,000 signatures with the Secretary of State’s office Monday, and Colorado Politics reports the candidate is confident he will qualify for the ballot.

Candidates have until Tuesday to file for the petition route and must submit 12,000 signatures by fellow Republicans to qualify.

Otherwise, candidates will have to get 30% of delegate support at the assembly, which means the field could be cut in half by the June 28 primary.

Meanwhile, Republicans Gino Campana, Deborah Flora, Greg Moore, Ron Hanks and Peter Yu are letting voters know how they would serve them better than Democrat U.S. Sen. Michael Bennet, or traveling the state to meet with voters.