The United States Department of Justice is reportedly investigating the PGA Tour regarding potential anticompetitive behavior in its response to LIV Golf, per Louise Radnofsky and Andrew Beaton of the Wall Street Journal.

The DOJ's antitrust division has contacted players' agents to discuss the PGA Tour's bylaws as well as the organization's recent actions related to LIV Golf.

Several high-profile golfers have joined the upstart league, which is backed by Saudi Arabia's Public Investment Fund, including Phil Mickelson, Dustin Johnson and Brooks Koepka.

The PGA Tour announced in June that it was suspending players who competed in the LIV Golf inaugural event, while those who resigned their PGA membership would no longer be eligible to compete in Tour events.

The PGA Tour recently made changes to convince golfers to stay, including increased purses and a smaller schedule, but others continue to defect amid high reported signing bonuses.

"We welcome good, healthy competition. The LIV Saudi Golf League is not that," PGA Tour commissioner Jay Monahan told reporters last month. "It's an irrational threat, one not concerned with the return on investment or true growth of the game."

The investigation by the Department of Justice could be a further blow to the PGA Tour, although the organization is seemingly undeterred.

"This was not unexpected," a PGA Tour spokesman said of the new probe. "We went through this in 1994 and we are confident in a similar outcome."

As noted by the Wall Street Journal, the Federal Trade Commission examined the PGA Tour's anticompetitive practices in 1994 but ended the investigation by 1995.

One rule the FTC looked into was the ban on players competing in a non-PGA event without the commissioner's permission. This remains a key part of the story as players were not given a release to compete in last month's LIV Golf International Series event in London.

LIV Golf participants are currently still eligible to compete in majors, which are not run by the PGA Tour, but other events like the Ryder Cup could be affected.