Sen. Mike EnziMike EnziSenate panel might not take up budget until October Debt group urges GOP chairman to avoid budget 'gimmicks' Fiscal hawks call for ‘mini-bargain’ on budget MORE (R-Wyoming), the ranking member of the HELP Committee, says he's optimistic about the possibility of bipartisan healthcare reform, according to the AP.

The article doesn't directly quote Enzi, but I'll trust this characterization:
Sen. Mike Enzi said he's still optimistic about the possibility of a bipartisan health care bill--even as he accused Democrats of not involving Republicans in the legislation.

Enzi has said that Democrats are "locking Republicans out of the process."

[snip]

But Enzi likes an idea proposed by Sen. Kent Conrad, D-N.D., to set up nonprofit cooperatives that would enable groups to put together their own health care plans.

The HELP Committee will share jurisdiction over healthcare with the Finance Committee, making Enzi one of the two most important Senate Republicans on the issue (along with Chuck GrassleyChuck GrassleyWhite House clarifies: We condemn all violence Republican lawmakers criticize Trump response to Charlottesville Grassley reverses ‘expectation’ of Supreme Court vacancy this year MORE, RM of Finance.)

The co-op idea is gaining momentum with centrists as a politically palatable alternative to a public option (or "government run healthcare," if you prefer.) The administration still wants a public plan, so the test is how hard they can push for it without falling below 50 votes.