Oaktree holds 14.8 percent of Tribune's shares, making it the third-biggest shareholder.
Oaktree also stated that "in the event one or more other parties express an interest in acquiring [Tribune]," it should be open to discussions with the parties.
On May 9, Tribune said its board had adopted a shareholder rights plan, popularly known as a "poison pill," in a bid to thwart Gannet's unsolicited takeover offer.
(Reporting by Marcy Nicholson; Editing by Chris Reese)