PRESEASON EXPECTATIONS: The San Francisco Giants are World Series champions this morning in large part because of their bullpen, which included situational lefties Jeremy Affeldt, Javier Lopez and Jose Mijares. The team they defeated, Detroit, had Phil Coke in that role. Most of the playoff teams had dependable lefthanded relievers. When the Mets went to spring training, a situational lefthander was a huge void they expected only Tim Byrdak to fill, which put them at a disadvantage. Byrdak bounced around with Kansas City, Baltimore, Detroit and Houston before finding a home with the Mets in 2011, when he appeared in 72 games and struck out 47 hitters in 37.2 innings. Meanwhile, other lefties in the Mets’ system, Josh Edgin and Robert Carson, were simply blips on their radar. Perhaps they’d get called up in an emergency or in September. Either way, neither was counted on for this season.

WHAT THEY GOT:  By his own admission, manager Terry Collins said he overworked Byrdak, who, like Pedro Feliciano before him, landed on the disabled list with arm problems. Byrdak appeared in 56 games and threw 30.2 innings. A reliever’s workload is more than innings, it is appearances, and with each appearance comes one or two times warming up in the bullpen. The Mets monitor warm-up pitches in the bullpen and knew Byrdak approached a dangerous limit. Eventually, those pitches took a toll and Byrdak was burned out. The strain was more magnified because he was the only lefthander. The Mets eventually replaced him with Carson and Edgin, both of whom performed well in spots. Edgin threw 25.2 innings in 34 games, and allowed seven of 23 inherited runners to score, a number that needs improvement. Carson has outstanding stuff, evidenced by a Sept. 12 appearance at Washington when he inherited a bases loaded-no outs situation an escaped unscathed. They lost that game, but it was arguably the Mets’ best appearance by a reliever all season. Only one of Carson’s six inherited runners scored.

LOOKING AT 2013: Admittedly, the windows of performance from Edgin and Carson are small, but both are inexpensive options for next season. As the Giants proved, having more than one lefty specialist is essential. The Mets abused Feliciano and Byrdak because they had nobody else, but having two will ease the burden, especially because they seem safe in the eighth and ninth innings with Bobby Parnell and Frank Francisco. Both will likely go into spring training with a spot on the staff. It has been a long time since the Mets had two dependable lefty relievers at the same staff.