PORT ST. LUCIE, Fla. -- The Mets took the field earlier this week with their Opening Day lineup mostly intact for the first time this spring: A converted first baseman was starting in right field. Another natural first baseman was at second base, with yet another at catcher. A second baseman started at third, and a longtime left fielder contemplated a switch to center -- though that will only happen if a former pitcher and two natural infielders do not beat him to the job.

Follow? Such is the unorthodox depth chart of the Mets, whose unique circumstances and personnel mix have created a bizarre mashup of fielders playing out of position.

It could be an issue. By most measures the Mets were a poor defensive team last season, ranking 25th in fielding percentage and last in Fangraphs.com's Ultimate Zone Rating, a more advanced -- though equally flawed in small samples -- measure of defensive worth. The Mets also ranked 28th in statistician John Dewan's Defensive Runs Saved system, as chronicled in Dewan's triennial "Fielding Bible."

That much, Dewan says, may not change in 2012. Dewan, whose company, Baseball Info Solutions, sells its findings to Major League teams, bases much of his foreboding on the fact that so many Mets fielders will play out of position this season.

According to Dewan's data, for example, right fielder Lucas Duda -- a natural first baseman -- cost the Mets a dozen runs on defense in half a season last year. Even taking into account some modest improvements, Dewan still projects Duda to cost 13 runs this summer.

"We're at the point where we think we've really got a good handle on measuring defense," Dewan said. "It was always the holy grail of 'How can you figure out how to measure defense?' And we think we've reached a very good spot now where we've got a good handle on measuring defense."

The basis of Dewan's data, which front offices across the game have adopted to various degrees, is a Plus/Minus system that rates how often fielders make plays compared with their peers. Duda, for example, did not reach many balls in 2011 that other right fielders around the game did. David Wright, Jose Reyes, Angel Pagan and Justin Turner all ranked quite low for the Mets as well, bringing down their defensive reputations.

And yet there is reason for hope. The Mets were actually one of the game's strongest defensive teams in 2010, largely due to five months of having Ike Davis at first base, a strong year from Pagan in center field and adequate performances at the corner outfield positions. But 2011 saw Davis' ankle injury, Pagan's diminished play, Duda's exposure to the outfield, and poor defensive output from Wright and Reyes.

But the front office has reason to believe that the 2012 team can outperform its projections. A full, healthy season for Davis, for example, should improve the defense at first base. The switch from Reyes to Ruben Tejada at shortstop might actually improve the up-the-middle defense, even if Daniel Murphy struggles at second. The shift from Pagan to Andres Torres may likewise bear fruit.

Then there is the matter of the fences at Citi Field. Since the Mets first announced changes to their dimensions back in October, team executives have preached that a smaller outfield will improve their outfield defense. Dewan's data is not built to account for such changes, though he agrees they could have significant impact.

"It theoretically makes sense," Dewan said. "Just like contouring any park to your strengths and weaknesses, that's going to help their defense."

Still, some Mets are skeptical of the data.

"Everyone thinks they have it figured out," said left fielder Jason Bay, who actually rates well on Dewan's system thanks to his ability to limit mistakes. "There are all these new metrics that will modify defense, but ultimately, they're all different."

Dewan understands that argument. As do many statisticians, he also acknowledges that there is an overriding human element to the game -- that, for example, Duda can improve as he becomes more comfortable in right field, and that Murphy can grow around the second-base bag.

Recently, such anecdotal evidence has surfaced for Murphy and Tejada in particular, with the pair turning three smooth double plays over their last two games. Each double play, Murphy says, felt "a hair more comfortable" than the last.

"There's no question Dan Murphy is going to do the exact job we all thought he would do," said manager Terry Collins, one of the strongest advocates for Murphy as a middle infielder. "That is, he's going to make the plays that he's supposed to make. Like anybody else, he's going to once in a while bobble a ball that he thought he should make. But it's not because of his inexperience."

Nor is it because of numbers on a page, no matter how accurate -- or unflattering -- a picture they may paint.

"You work with a fielder, and they can get better," Dewan said. "I always think of Wade Boggs taking, like, 1,000 grounders a day. You've got to get better with practice, and I truly believe that will happen."