Herbert announced at his monthly televised news conference on Thursday that "doing nothing" to expand the program was off the table.
The governor said he had made a decision about what path to take, but he declined to give details.
Herbert said he'd announce his decision during the Legislative session, which starts Monday.
Under the federal healthcare law, states have the option of expanding eligibility for Medicaid, the state-federal program for low-income people.
If states expand the program to include people making up to 138% of the federal poverty level, the federal government has offered to pick up the full cost through 2016 and 90% after that.
Because of a gap in the healthcare law, there are about 60,000 Utah residents who are currently not covered by Medicaid or eligible for federal subsidies to pay for private insurance.
"That's not right. That's not fair," Herbert said. "I'm going to work with the Legislature to find a solution to that problem."
Herbert has repeatedly stated his opposition to the healthcare overhaul, but he said Utah must now deal with it because it's the law.
He and other Republican officials in Utah have been reluctant to take up the offer to fully expand the program. They have cited concerns about the sticker price and whether federal budget strains may cause Washington not to hold up its end of the agreement.
A state panel studying the issue recommended three options in November. One option was to do nothing. Two others would partially expand the program and use tools such as subsidies for others to buy private health coverage.
Democrats have pushed for full expansion, arguing it's the right move morally and for state finances.
If Utah fully expanded the program, about 130,000 uninsured people would gain coverage under Medicaid. That's in addition to the 225,000 to 250,000 people already on the program.