Flushing, NY -- (Sports Network) - New York Mets closer Billy Wagner suffered a further setback and could possibly be out for the rest of the season due to his left elbow problems.

Wearing a protective sleeve on his left elbow, Wagner tested his arm Sunday between games of a day-night doubleheader against Philadelphia and threw pitches to teammate Gustavo Molina.

He hit the reserve catcher on the left foot with his 13th pitch and walked off the field to consult with a trainer and the Mets' coaching staff. The left- hander was expereincing discomfort in the elbow and will be re-examined by a doctor on Monday.

Wagner has been out since August 3 due to the injury.

The 37-year-old lefty is 0-1 with a 2.30 ERA and 27 saves in 34 chances this season.