It’s been said that spring is when you feel like whistling even with a shoe full of slush. And given their winter spending spree, the Mets have reason to chirp.

For wary fans, however, the team’s bullpen is the cold splash of reality that rudely interrupts October dreams. The difference between a very good pen and a very bad one is estimated to be around 100 runs a year – the margin between a pennant race and another spring housecleaning. The Mets’ pen performed at a league-average level in 2004, but this spring, it is stocked with retreads, injury-rehab cases, imports, and rookies. How much manager Willie Randolph can coax out of this ragtag bunch will go a long way in determining whether the team contends this year.

For now, at least, it looks like the Mets are on the right track. With veterans Ricky Bottalico, Mike Stanton, and John Franco out of the picture, GM Omar Minaya has chosen to bridge the gap between the starters and closer Braden Looper with a wide array of low-cost options. In resisting the urge to land a big name during the off-season, Minaya maintained some payroll flexibility and held onto the team’s valuable commodities. The strategy could fail, of course, but Minaya could well be vindicated if some of the team’s promising young arms seize the chance to prove themselves.

The Mets appear satisfied with Looper after a 2004 campaign in which he maintained a 2.70 ERA in 83.1 innings. The former Marlin sported control that was significantly better than expected – he had a K/BB ratio of 3.8, as compared with 1.9 in 2003 – and he was stingy with the long ball (five in 83 innings). His hit rate was higher than you’d like for a closer, but that’s to be expected given his proficiency at inducing groundballs (1.8 for every flyball versus 1.2 for the average pitcher). It’s reasonable to expect Looper to again be solid in 2005.

The presumptive set-up man, Mike DeJean, wasn’t nearly as bad for Baltimore as he was unlucky with batting average allowed on balls hit in play. For the O’s, DeJean allowed hits on over 40% of balls put in play, which translated into a 6.13 ERA; as a Met, that number declined much closer to the league average of 30%, and his ERA was a miserly 1.69 in 21.1 innings. Another key to his success with the Mets was superb control (4.8 K/BB ratio) before he broke his leg in August. At worst, Dejean should be an adequate set-up man; if his late-season control last year wasn’t an illusion, he could be very good.

The primary lefty looks to be Korean import Dae-Sung Koo. Though Koo’s numbers as a starter in the Japanese League were not impressive – he has surrendered almost four walks per nine innings over his career and gave up a whopping 24 homers in 116 innings last season – it’s also important to note that he recorded more than a strikeout per inning.

When starters move to the bullpen, their strikeout rates tend to spike significantly; Eric Gagne, for example, averaged seven strikeouts per nine innings as a starter and over 12 as a reliever. Also, given that San Diego’s Akinori Otsuka’s Japanese strikeouts translated reasonably well last year and that White Sox closer Shingo Takatsu dramatically improved on his Japanese relief numbers in the A.L.’s toughest pitching park, the 34-year-old Koo could fare well in pitcher-friendly Shea.

The team’s second lefty, Yankee reject Felix Heredia, offers little upside, and savvy Mets fans may be hoping that he struggles so badly this spring that the team is forced to turn elsewhere. If Heredia is released, the Mets should audition minor-leaguer Blake McGinley, who, at 25, was long in the tooth for Double-A and Triple-A last year but continued to excel in the Venezuelan League (20/4 K/BBs in 14 relief innings). Scouts feel he has pedestrian stuff, but the numbers suggest he knows how to use it.

The most likely of the remaining candidates to make the trip to Shea is righty Scott Strickland, who has a good chance of becoming a serviceable right-handed power arm nearly two years removed from Tommy John surgery. Beyond that, the Mets should avoid keeping retreads like Roberto Hernandez or the recently retired Todd Van Poppel at the expense of the several young power arms in camp.

One, Heath Bell, pitches the way you would expect from someone listed at 6-foot-2 and 244 pounds: The young flame-thrower struck out 27 in 24 big-league innings last year but was prone to the gopher ball (five homers). Another, Bart Fortunato is loose and lean with mid-90s heat and 10.4 Ks per nine innings as a pro, though he did walk 15 batters in 26 big-league innings last year.

Two others, Aaron Heilman and Orber Moreno, are disappointing prospects trying to salvage their careers; Heilman has averaged seven strikeouts per nine innings in about 100 frames as a big-league starter and could boost that to double digits as a reliever if the Mets facilitate such a move.

All told, the Mets are faced with difficult decisions regarding the pen, especially if DeJean, Strickland, or Koo falter early on. Flushing fans should hope that Randolph and pitching coach Rick Peterson have enough moxie and patience to develop young arms like McGinley, Bell, and Fortunato into high-leverage, late-inning relievers.

Failing that, the Mets will be in the long line of suitors targeting some noncontender’s middle reliever come July. Prospects will be required, and given how the Mets overpaid at the deadline last year, the mere fact that the team has a new GM isn’t going to stop every front office in baseball from trying to extract top dollar.