The United States Justice Department is investigating the PGA Tour for potential antitrust violations related to its competition with the Saudi-backed LIV Golf.

The PGA Tour confirmed news of the probe to the Wall Street Journal.

“This was not unexpected,” the PGA Tour spokesman told the outlet of the investigation. “We went through this in 1994 and we are confident in a similar outcome.”

In 1994, the Federal Trade Commission investigated whether it was legal for the PGA Tour to require players to get permission to play outside events and otherwise regulate their appearances on other golf TV programs. The FTC ultimately dropped the probe.

LIV Golf has been throwing hundreds of millions of dollars at established golfers to defect from the PGA Tour and has nabbed stars including Phil Mickelson, Brooks Koepka, Bryson DeChambeau, and Dustin Johnson.

The PGA Tour has responded by indefinitely suspending all golfers who took the money from LIV.

In February, when PGA Tour commissioner Jay Monahan threatened players that they would not be permitted to compete in both circuits, LIV Golf’s figurehead, Greg Norman, issued a legal threat in a letter: “Surely, your lawyers at the PGA Tour must be holding their breath.”

“[W]hen you try to bluff and intimidate players by bullying and threatening them, you are guilty of going too far, being unfair, and you likely are in violation of the law,” Norman continued in his letter to the PGA Tour. “Simply put, you can’t ban players from playing golf. Players have the right and the freedom to play where we like.”

Norman has repeatedly downplayed human rights concerns attributable to being financially backed by the Saudi regime.

Legal battles over LIV Golf have also occurred overseas.

Last week, a group of golfers, including Ian Poulter, won an injunction from a British court to be permitted to play in the Scottish Open on the DP World Tour (formerly the European Tour), which had similarly barred LIV Golf players from competing.