If so, one needs to drop out.
I was mistaken. According to www.politics1.com, these candidates are at least considering that race:
Mike Flynn (R) - Political Consultant & Conservative Blogger
Kent Gray (R) - Community College Trustee
Darin LaHood (R) - State Sen., Attorney & Son of Ex-Congressman Ray LaHood
Mark Zalcman (R) - Attorney & ‘14 State Rep. Candidate
Flynn and LaHood said that they’re running. Gray hasn’t announced whether he’s running. Zalcman dropped out, but he said that he’ll run in the 2016 primary.