The 26-year-old will be out of contract at the end of June, and has already informed Fulham of his decision to not renew.
Newcastle boss Eddie Howe is a known admirer of Tosin, and it is also understood that Manchester United are in the race.
Eric Ten Hag’s side are in a tight financial position this summer with FFP regulations, but are interested in strengthening their defence.
A free transfer might be key for the 20-time English Champions.
