NEW YORK -- Late this summer, Mets general manager Sandy Alderson came to the definitive conclusion that Citi Field's outfield dimensions were unfair to hitters.

"You just kept looking at that thing, and that left-field wall kept getting higher and higher," Alderson said.

So he did something about it. The Mets on Monday announced drastic plans to alter Citi Field's dimensions, lowering some walls, moving in others and painting the entire outfield fence blue.

The new layout will add roughly 140 seats to Citi's capacity and undoubtedly result in more home runs and a more neutral playing environment.

"You don't want the ballpark to be a distraction," Alderson said. "And I really do believe a ballpark like ours has a more dramatic impact on the home team than on the visitors."

From left to right, the first change will take place where the old left-field wall reaches its apex of 16 feet. The Mets plan to construct an eight-foot wall in front of the permanent 16-foot one, angling it toward center field to create a wedge-like shape. In the space between the walls, the team will construct approximately 100 new seats, including traditional seats and bar stools.

The wall will not change in straightaway center field save for its new color, before angling again to cut off the old 415-foot gap in right-center. The new gap will stand 398 feet from home plate, resulting in a patch of empty space between it and the existing wall.

From there, the fence will follow its old course until it reaches the "Mo Zone," where a new wall will cut off the existing irregularity. That will allow the Mets to expand their popular Modell's Clubhouse group seating area to include roughly 40 additional outdoor seats in prime home run territory. Despite declining attendance, the Mets sold out that area last season and have sold 99.5 percent of Modell's Clubhouse seats since the park's opening in 2009.

In sum, the new dimensions will reduce Citi Field's overall playing surface by slightly less than two percent. According to the Mets' projections, that layout would have resulted in 151 more home runs over the past three seasons -- 81 more for the Mets and 70 more for their opponents.

"We didn't want to completely alter the ballpark and make it a proverbial bandbox," Alderson said. "That required looking at various dimensions and coming up with something that, based on home run rates and park factors and so forth, was more or less neutral as between pitching and hitting."

There was no exact science to those measurements, because there was no precise way to discern how much of Citi Field's home run stinginess had been due to its dimensions and how much to the composition of the home team. But the Mets believe they came close in their estimations, studying the home run rates of the Mets and their opponents, as well as overall park factors and scatter plots of every fly ball hit at Citi.

To a small extent, Alderson also conferred with players, holding a clubhouse meeting to discuss the changes last month in St. Louis. The new dimensions figure to most benefit right-handed power hitters -- particularly David Wright and Jason Bay, who have seen drastic drops in their power production over the past two seasons.

Averaging 18 home runs per year since Citi Field opened in 2009, Wright hit 29 per season playing his home games at Shea Stadium from 2005-08. Bay also experienced a significant decline in power after signing with the Mets as a free agent, averaging nine home runs per year after hitting a career-high 36 with the Red Sox in '09.

For both players, much of that dip was due to injuries -- both nagging and acute. But Wright and Bay recently admitted that some of it may have been due to subtle, even unconscious adjustments given their home park's dimensions.

Citi Field ranked third-to-last in the Majors last season with 1.33 home runs per game, according to the Elias Sports Bureau.

"I think the word 'fair' really applies here," Bay said Monday in a text message. "It's no secret it was a big ballpark and still is by a lot of comparisons. But in theory it should help the hitters and the defense, which indirectly helps the pitching staff. And we should benefit slightly more given that we play 81 games there."

As Bay noted, the Mets believe the new layout will alter defensive positioning enough that it will not hurt their pitching staff to any great extent.

On the opposite end of the spectrum, the new dimensions could potentially hurt free-agent shortstop Jose Reyes, who hit 12 of his 16 triples at home last season -- many of them into Citi's once-expansive right-center-field gap. Though the Mets remain unsure if Reyes will return next season, they did factor him into their calculations.

But in the end, the promise of more home runs was enough to sway Alderson, who believes that offense sells tickets more effectively than pitching.

"I don't want to give you the impression that we've done this for David or we've done this for Ike [Davis] or we've done this for anyone in particular," Alderson said. "It's really about having a more neutral ballpark."

It is also about having a more fan-friendly ballpark. Due in large part to fan feedback over the last three seasons, the Mets will paint the new wall blue instead of black. The orange home run line will remain, as will the black metal railing atop the left-field wall.

Construction on the new walls could begin as soon as mid-November and take six to eight weeks, though the team may wait until springtime due to weather concerns. Opting not to disclose the project's cost, the Mets did say that it fits into the surplus of the ballpark's original $800 million budget.

"We're trying to fit into the more 'normal,'" Mets COO Jeff Wilpon said of the new dimensions. "But if it's a little bit above that or a little bit below, we think we've got a big enough sweet spot that it's not going to matter."