Slap-happy from crazy work week + Canadians = This won’t be good.

The Major League left fielders in April: Jason Bay, Frank Catalanotto

One tenet of the Abraham Nunez Axiom is that when the Mets are deciding between two players to back up a lesser player (in this case, Mike Jacobs), they’ll choose the one with less upside. And so the Mets have Catalanotto on the club, and not Chris Carter.

Overview: Jason Bay is a polite Canadian power hitter. He seems happy that his ability to hit home runs and get on base earned him a four-year, $66 million contract this offseason, but he has told reporters he would also be happy in the career he thought he would pursue after college: zinc smelting. That’s no joke. He had an internship lined up and everything.

You don’t just jump right into paid work at the zinc-smelting plant. You have to cut your teeth first, pay your dues. Do whatever zinc-smelting interns do. Our interns at at the SNY digital department do stats research and figure out what we’re going to talk about on New York Baseball Today and try to figure out ways to get people to visit our websites, which is basically all stuff I do, only they don’t get paid for it. So maybe zinc-smelting interns just smelt zinc for free. Suckers.

I don’t know where zinc comes from and I don’t know how zinc gets smelted, exactly. I think the process is used to create a specific type of sunblock found most frequently on the noses of 1980s lifeguards. In that case, it’s probably good Jason Bay went into power hitting, because no one wears that stuff anymore.

What I do know is that Bay will hit home runs, even in Citi Field. Though Bay benefited from Fenway Park’s dimensions in 2009, his new home does appear to play well for right-handed pull hitters, and he’s one of those.

He’ll also likely get on base around 38% of the time, if not more. That’s good, especially since the Mets will field an Opening Day lineup that includes two guys — Mike Jacobs and Rod Barajas — who couldn’t muster a .300 on-base percentage in 2009 and several more who hovered only barely above that mark.

The main downside to Bay is that it may at times appear the Mets would be better off replacing him in left field with a solid block of zinc. By both UZR and +/-, Bay ranked among the worst left-fielders in the Majors last season, and to the eye this spring, he has appeared slow-footed in pursuit of balls hit to the gaps.

The other downside is that the Red Sox supposedly backed off their pursuit of Bay due to concerns that he would eventually need knee surgery. Who knows?

Unless and until that happens, Bay’s steady production from left field should come as a welcome relief for a team that has fielded such luminaries as Cory Sullivan, Jeremy Reed, Wilson Valdez, Damion Easley, Marlon Anderson and David Newhan (among other, better-hitting players) in the spot in the past three years.

The Major League left fielders in September: Bay and Angel Pagan.

Assuming Carlos Beltran returns to health, Pagan becomes the primary backup outfielder. That may not necessarily spell the end for Catalanotto, of course. I’m speculating on the fringes of the roster in September. We’ll see what happens.

How they stack up: I don’t think Raul Ibanez is likely to repeat his 2009 performance on either side of the ball in 2010, meaning Bay is probably the class of the N.L. East left-fielders. The Marlins’ Chris Coghlan is a nice young player who will only get better, but he doesn’t have the power to stack up to Bay just yet.