Update 5/19 @ 11:03am: 

The Mets have optioned 2B/SS Jordany Valdespin to make room for Jeremy Hefner. Since the Mets will probably find the idea of a four-man bench not all that favorable, another move will likely be made in the coming days, probably Acosta will go down. Hefner will wear #53 and Valdespin will primarily play second base in Buffalo.

Original Post 5/19 @ 8:26am:

The Mets organization plans to call up RHP Jeremy Hefner prior to tonight’s ballgame at Toronto reports Adam Rubin of ESPNNewYork.com.

Though no formal announcement has been officially made, Adam Rubin cites Manny Acosta as the most logical candidate to get the boot, whose ERA leaped to 10.53 after yet another unsightly outing from the 31-year old righty.

Hefner was called up as the 26th man on the roster for a double header with the Giants and hurled three scoreless frames of relief before being sent back to Triple-A.

Other Mets getting promotions include Adrian Rosario and Jack Leathersich. Rosario has been dominant to start the year in St. Lucie, striking out 28 while walking only seven in 20 1/3 innings, not to mention 11 saves and a 0.89 ERA to match. Rosario was acquired in the deal that sent Francisco Rodriguez to the Brewers last July along with Danny Herrera, who had Tommy John Surgery last month. K-Rod currently has a 4.96 ERA for Milwaukee in 2012.

Leathersich has been equally dominant, punching out a staggering 37 batters in 24 innings. Leathersich, who by the way had a 0.75 ERA with the Sand Gnats, will likely take Rosario’s place as co-closer with Adam Kolarek in the St. Lucie bullpen.