Centrists and GOP leadership were in talks on Wednesday to add $8 billion to high-risk pools and other changes to get them on board a precarious effort to repeal Obamacare.

The potential changes come as Republicans get ready to leave for a 10-day recess that starts on Friday.

Rep. Fred Upton, R-Mich., who stunned GOP leadership by defecting and planning to vote against the repeal bill, is pushing an amendment to give $8 billion to high-risk pools, he told the Associated Press late Tuesday.

Upton's amendment would give high-risk pools $8 billion over five years. This would be on top of $15 billion provided in an amendment that sets up the risk pools.

Republicans have also pointed to a $115 billion stability fund that states can tap to fund high-risk pools, where the state subsidizes coverage for people with pre-existing conditions.

However, the $115 billion fund isn't dedicated to only high-risk pools. It was created to help stabilize premiums in individual markets; $15 billion of that is designated for mental health services.

It remains unclear whether an additional $8 billion is enough to fund the pools, as some experts have said that it will cost much more.

However, Republicans said on Tuesday that not everybody would need the pools. An earlier amendment to the American Health Care Act authored by Rep. Tom MacArthur, R-N.J., would let states opt out of regulations that could let insurers charge people with pre-existing conditions more.

MacArthur and other Republicans said Tuesday that not every state would take up the waiver, and that even then, people with pre-existing conditions aren't affected if they have continuous coverage.

He told reporters that he doesn't think adding money for high-risk pools could be enough to get wary centrists on board. Upton said on Tuesday that adding money wouldn't be enough to get his support.

However, Upton's amendment would create a fund that pays a penalty for people who are not previously insured but get priced out of the marketplace due to their health status, according to a report in Axios.