Flushing, NY -- (Sports Network) - New York Mets closer Billy Wagner will be out indefinitely as he is experiencing more pain and swelling in his left elbow.

Wagner had an MRI exam at the Hospital for Special Surgery in New York on Tuesday that revealed the additional inflammation in his throwing elbow.

Wagner was placed on the disabled list on August 5 and was expected to be activated this week, but it was revealed on Saturday that he was still experiencing discomfort in the elbow after throwing around 20 pitches in a simulated game.

It is unknown when the 37-year-old lefty, who is 0-1 with a 2.30 ERA and 27 saves in 34 chances this season, will be able to pitch again this season.

The Mets, who have been using a closer-by-committee approach without Wagner, acquired righty Luis Ayala from Washington on Sunday in an effort to bolster their bullpen.