Appearing on "Fox & Friends" with hosts Ainsley Earhardt, Steve Doocy, and Pete Hegseth, Napolitano explained that the justices agreed to hear the case last week because of a "change of membership on the Supreme Court."
The Louisana law – upheld by a federal appeals court – requires that doctors performing abortions have "admitting privileges" at a nearby hospital. The law is notably similar to a Texas law struck down in the Supreme Court only three years ago.
In February, the high court blocked enforcement of the law, while further legal appeals were being filed. Chief Justice John Roberts sided with his more liberal colleagues at the time.
Additionally, four Justices can compel the other five to hear a case, because there does not have to be a majority.
"So, theoretically, the four most conservative Justices – Thomas, Gorsuch, Kavanaugh and Alito – could very well have decided that the decision to invalidate the Texas law three years ago needs to be changed," Napolitano added.
"And, it is probably, more pro-life," he said. "So, they probably want to review this opinion to decide if they can uphold it."
Napolitano continued, explaining that the "fear of the pro-choice crowd" when it comes to this case is that "this new Supreme Court will allow the states to narrow the circumstances under which an abortion can be had."
Abortion rights supporters say Act 620 is too restrictive and places an "undue burden" on a woman's access to the medical procedure. They say it would leave the state with just one abortion clinic.
Supporters of the law say it is a reasonable regulation, with attorneys saying in court filings on behalf of Louisiana Health Secretary Rebekah Gee that "Louisiana abortion clinics have a history of serious health and safety problems."
"Louisiana argues it's for the health and safety of the mother and of the fetus. The other side says it's a subterfuge to narrow the circumstances under which abortions can be had. The court will decide it," Napolitano said.
"Here's the thing: the decision's going to land right before the Democratic National Convention and the Republican National Convention next spring," he told the "Fox & Friends" co-hosts. "Whichever way it goes, it's going to be a bombshell!"
The high court will now set a briefing schedule, with oral arguments early next year and a ruling expected by June 2020.
Shannon Bream and Bill Mears contributed to this report.