After trying to survive an entire season with just one left-hander in the bullpen, the Mets came to their senses and called up southpaw Justin Hampson from Triple-A Buffalo.

Hampson was 4-2 with a 2.13 ERA and two saves in 28 appearances with Buffalo, and lefty batters are hitting .218 against him this season.

Hampson, 32, has a career 3.38 ERA in 79 appearances (one start) for the Rockies and Padres from 2006 to 2008.

He’ll now join Tim Byrdak as the second left-hander in the Meta bullpen. The Mets designated Vinny Rottino for assignment to make room for Hampson.

Yesterday, the team placed closer Frank Francisco on the DL with a strained oblique and activated reliever Ramon Ramirez. Bobby Parnell is expected to get most of the save opportunities while Francisco is out.