Reps. Jeb Hensarling and Pete Sessions, both conservative Texas Republicans, said Thursday they would not challenge McCarthy, the majority whip, who appears poised to move up the GOP leadership ladder.
Sessions had said Thursday he was confident he could beat McCarthy and inject conservatism into the House leadership, but by the end of the day, he bowed out.
"After thoughtful consideration and discussion with my colleagues, I have made the decision to not continue my run for House majority leader," Sessions said in a statement. "Today, it became obvious to me that the measures necessary to run a successful campaign would have created unnecessary and painful division within our party."
House Speaker John Boehner, R-Ohio, refused to endorse any single candidate, instead saying Thursday he has worked "with all 434 other members of Congress before" and would do so with whomever was elected as his deputy.
But late Thursday night, Rep. Raul Labrador, R-Idaho, said he may yet enter the race.
While on a flight to Salt Lake City, Labrador told the Washington Post he was considering a run, although "it's not something I've been planning."
Labrador said many of his conservative colleagues had reached out, urging him to run. Some members have said they would prefer a leader from a red state, like Idaho, rather than a blue or purple state, such as California. And would he win the job, Labrador, 46, would be the first Hispanic and first Mormon to serve as leader.
All 233 Republican caucus members will cast secret ballots next Thursday to determine Cantor's successor, who will take on the job after Cantor steps down July 31.