Rep. Jim Renacci, who entered Ohio's gubernatorial race in March, made the announcement on CNN's "New Day" coming as Republicans are two "no" votes away from another failure on their efforts to repeal and replace Obamacare.
"I was a supporter prior to this amendment. I'm now a supporter after the amendment," the Republican told CNN's Alisyn Camerota. "Pre-existing conditions will be covered. The real issue here is this amendment gives flexibility to states."
New Jersey Rep. Tom MacArthur, a moderate Republican, and leaders of the conservative House Freedom Caucus cut a deal last week that would require insurers to cover those with pre-existing conditions but, unlike the mandate under Obamacare, insurers could charge them higher rates than others in the plan if they allow their coverage to lapse.
The amendment would allow states to seek waivers to weaken several key Obamacare insurance reforms that protect those with pre-existing conditions, including the benefits insurers must cover in their policies and the ban on allowing carriers to charge more based on a person's health background.
Health care experts say this change could leave those with pre-existing conditions, such as diabetes and asthma, paying much higher premiums and potentially facing gaps in coverage.
But Renacci said giving governors this flexibility is valuable because governors understand that there are "massive differences" between his state and others.
"I believe governors know what's best for states like mayors know what's best for cities," Renacci said. "The closer you get to people, the better it will be. I'm a big believer in letting those decisions be made at state level."
"If the governors decide to remove that, that's something they are going to have to do within the constraints of the people they represent," he added.
The American Medical Association said in a letter urging lawmakers to oppose the legislation that the switch to high-risk pools "could effectively make coverage completely unaffordable to people with preexisting conditions."
But Renacci dismissed the idea that allowing governors to opt out will leave some people without health care coverage.
"I don't believe that," Renacci said. "I don't believe there's any governor out there who is going to try and eliminate coverage. I think what the governors will do is design programs that best fit their states, make sure it's designed for the people in the state."