The 32-year-old Jupiter resident and four-time major champion is the latest professional golfer to break from the PGA Tour to join the Saudi-backed invitational.
LIV Golf is expected to announce the addition of Koepka, 32, in the coming days, sources told ESPN on Tuesday.
The No. 19-ranked golfer in the world would reportedly join LIV Golf in time for its first U.S. tournament in Oregon at the end of the month, ESPN reported.
His addition to the LIV Golf circuit would give it eight of the top 50 players in the world, including several with ties to Palm Beach County.
PGA Tour Commissioner Jay Monahan has already suspended 17 golfers, including Phil Mickelson and Dustin Johnson. Mickelson is building a house on Jupiter Island.
Koepka, who competed in last week's U.S. Open, chastised reporters for "throwing this black cloud" over the PGA Tour major by repeatedly talking about LIV Golf.
"I'm here at the U.S. Open," Koepka said. "I'm ready to play the U.S. Open, and I think it kind of sucks, too, you are all throwing this black cloud over the U.S. Open.
It's one of my favorite events. I don't know why you guys keep doing that. The more legs you give [LIV Golf], the more you keep talking about it."