Jon Niese injury: Mets LHP has MRI pushed back until Monday

The fate of Jon Niese's 2013 season will be up in the air for a few more days. The New York Mets left-hander was scheduled to have a follow-up MRI on his injured throwing shoulder Thursday, but the appointment was pushed back to next Monday because the team doctor is on vacation through the holiday weekend, reports Adam Rubin of ESPN.

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Niese, 26, was pulled from his June 20 start in Atlanta after feeling a sharp pain in his left shoulder and was placed on the DL the following day. Team physician David Altchek diagnosed the southpaw with a partially torn rotator cuff and prescribed two weeks of rest and physical therapy in the hopes that surgery could be avoided.

Now that his two weeks are up, Niese's destiny rests in the hands of Dr. Altchek and his MRI machine -- once Altchek gets back from the Hamptons, that is. Monday's follow-up exam should determine whether Niese can continue on a natural rehab track or if he needs a season-ending operation.

Niese has battled with shoulder issues for much of the season, missing a start at the beginning of June with what the team termed tendinitis, but his recent tear is believed to be a wholly separate injury.

Niese's performance has taken a rather large step backward this year following his breakout 2012 campaign. Through 14 starts this season, the southpaw owns a 4.32 earned-run average and a career-low 5.7 strikeouts per nine innings.

The Mets were expected to move either Dillon Gee or Jeremy Hefner to the bullpen upon Zack Wheeler's promotion to the big-league club, but with Niese out indefinitely, it seems that both pitchers will stay in the starting rotation for the time being.