Are PGA rules anticompetitive?

WSJ reports on a Dept of Justice (my old employer) investigation of the PGA which

... requires players to request a release to play in tournaments that conflict with PGA Tour events [no such releases are granted for events in North America].

The theory seems to be that these rules reduce competition by deterring entry, e.g., the Saudi-backed LIV tour. Under US law, plaintiffs would likely have to show that these rules tend to create or maintain a monopoly.