Most people understand baseball’s infield fly rule better than the concept of what makes up a proper health insurance policy. Previously, a majority of Americans didn’t have to worry because an estimated 55 percent were covered by a policy that someone else shopped for, based on their employment.  

But that cozy arrangement is changing, based on several market factors and a hidden clause in the Affordable Care Act.

While individual coverage for health care increased in the first half of 2014, it declined in the second half of the year, according to research tabulated by the Heritage Foundation from state government reports. That’s because employers stopped covering employee health insurance, offsetting about 85 percent of the individual coverage gains.

While there’s still a net gain in the number of people who now have health insurance, a lot of that gain was because of increasing numbers of low-income people signing up for Medicaid.

Overall, that means that more than 4 million people aren’t covered by employer-based health care plans. That leaves the uncovered with three choices if they wish to remain insured: get insurance on their own; find a new employer willing to cover their health insurance; or apply for the government-funded Medicaid.

There’s bad news on the horizon even if you’re covered. The so-called “Cadillac tax” will arrive in 2018 as part of the Affordable Health Care Act. That’s a 40 percent excise tax that will hit those who have an employer-provided health plan higher than a certain benefits level.