Familia can resume throwing in six weeks, with his return to "competitive pitching" estimated at three to four months.
The 27-year-old closer first reported feeling a tingling sensation in his right ring finger to a member of the Mets' training staff prior to Wednesday's 6-5 loss to San Francisco at Citi Field.
Familia was evaluated at that point and was cleared to pitch in the game, in which he blew the save and took the loss, recording just one out and allowing four runs (three earned).
Due to mild vascular symptoms, Familia was referred to the Hospital of Special Surgery in New York for a magnetic resonance angiography. The MRA, performed Thursday morning, revealed the blood clot.
Andrew Gruman is a contributor to MLB.com based in Milwaukee and covered the Mets on Saturday. This story was not subject to the approval of Major League Baseball or its clubs.