Or the law could increase the number of people with employer-based coverage by 3 million by 2019, the Congressional Budget Office said.
The CBO said besides those worst-case and best-case scenarios, its best estimate -- still with a "tremendous amount of uncertainty" -- is that there would be 3 million to 5 million fewer Americans with employer health coverage from 2019 to 2022, The Hill reported.
The update on the law's coverage provisions says the law is now anticipated to cover 2 million fewer people, but cost $50 billion less over 10 years, the newspaper reported. Last year, the CBO figure for the period was 1 million fewer.
The Hill said Republicans have blasted the new numbers because they appear to violate Obama's pledge that people who like their healthcare plans will be able to keep them.
But the White House contended the latest projections are in line with CBO estimates when it evaluated the legislation at passage in 2010.
"Today's report also does not project major changes in the number of workers who will get coverage through their job," Jeanne Lambrew, the deputy assistant to the president for health policy, wrote on the White House blog.
Meanwhile, the anti-abortion American Center for Law and Justice said in Washington it has filed a first-of-a-kind federal lawsuit against the Department of Health and Human Services on behalf of a Missouri business owner.
Frank R. Obrien and O'Brien Industrial Holdings LLC in St. Louis contend the HHS contraceptive mandate violates his constitutionally-protected religious beliefs. The lawsuit also requests a permanent injunction against requiring those who have religious objections to the mandate, which requires employers to buy health insurance for employees that includes coverage for "contraceptives, sterilization and abortion-inducing drugs."