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6/17/2013 8:06 P.M. ET

Turner could land on DL with left intercostal strain

ATLANTA -- Mets infielder Justin Turner is dealing with a left intercostal strain that could land him on the disabled list as soon as Tuesday.

Turner stayed in New York after Sunday's game, receiving an MRI on Monday morning before joining his teammates in Atlanta. Though the Mets may not reach a resolution before the start of Tuesday's doubleheader, manager Terry Collins strongly indicated that Turner could land on the DL.

"He's had it for a few days," Collins said. "He's just gotten worse the last couple days, so we had him looked at."

With the Mets scheduled to play five games in four days in Atlanta, and in need of roster spots to make room for pitchers Zack Wheeler and Scott Atchison, they may simply disable Turner and proceed with an extra arm for the immediate future. That would eliminate the need to cut anyone before Tuesday, thanks to an MLB rule that allows teams to carry 26 players for previously-scheduled doubleheaders.

But the Mets will still have to make another roster move after the doubleheader.

Turner is in the midst of an 8-for-50 slump, lowering his average from .378 at its peak to .266. He has made spot starts at all four infield positions, appearing most frequently at first base.

Mets shift Duda to first, Murphy back to second

ATLANTA -- Reversing course on last week's alternative defensive assignments, Mets manager Terry Collins scrawled out an entirely new lineup for Monday's series opener against the Braves.

Daniel Murphy, who spent a one-week tour of duty at first base, returned to his usual position at second. Meanwhile, Lucas Duda, who has worked tirelessly in the outfield for the past two years, shifted to his natural position at first.

"We just thought that's where he plays the best," Collins said of Duda. "He's excited about being back over there, which I think is a very positive thing. Dan wants to play second -- he's happy he's going back to second. We'll just see if it transforms into a productive lineup."

That alignment allowed the Mets to give Kirk Nieuwenhuis and Juan Lagares simultaneous playing time in left and center field, respectively, all while keeping right fielder Marlon Byrd's hot bat in the lineup.

As recently as last week, Collins said he would not consider moving Duda to first. But Jordany Valdespin's unsuccessful run as the everyday second baseman prompted the manager to change his mind.

"You're allowed to change," Collins said. "There's nothing etched in stone. You're allowed to make changes and you're allowed to make decisions that you think are in the best interests of the ballclub. Last week, we made decisions we thought were in the best interests of the club. They didn't work. So as I ask our players to adjust, I've got to do the same thing. I've got to make some changes."

A college first baseman, Duda did not begin playing the outfield regularly until his first professional season in 2007. He did not become a full-time outfielder until 2011, taking over in right after the Mets traded Carlos Beltran.

Since then, Duda has spent countless hours working to improve his outfield play, which most scouts still classify as decidedly below-average. At first base, the Mets hope that not only can Duda's defense become an asset, but that the assignment will also allow him to concentrate more fully on his hitting.

The catch? Putting Duda at first base may seem like something of a slight to Ike Davis, who has struggled since his demotion to Triple-A Las Vegas. But Collins said that once Davis returns, Duda will simply shift back to left.

"Obviously, I know it's Ike's position," Duda said. "I'm just there to help out the team anyway I can. I don't really feel like there's any awkwardness."

Costas calls Mets to apologize for comments

ATLANTA -- Terry Collins heard the quip. How could he not? NBC broadcaster Bob Costas generated headlines Sunday when he called the Mets' walk-off celebration evidence of "the decline of Western civilization."

"All right, civilization's over," Collins jabbed back Monday afternoon. "We'll have to rebuild it."

Running through highlights during NBC's coverage of the U.S. Open, Costas criticized the Mets for celebrating as if they had "just won the seventh game of the World Series," when in reality they simply moved to within 13 1/2 games of the first-place Braves.

A day later, Costas called Mets public relations guru Jay Horwitz to apologize.

"He's an intelligent guy," Collins said. "I don't really know what that all means. But I know one thing, we had a nice celebration."

In reality, Collins said, he would have been "a little concerned" had his team not celebrated the win, which Kirk Nieuwenhuis ended with a three-run homer off Cubs reliever Carlos Marmol. As Nieuwenhuis rounded the bases, the Mets ran out of the dugout and swarmed him at home plate.

"Show me a team that has a walk-off home run that they don't celebrate," Collins said. "Show me one. I've seen the Yankees do it, I've seen the Cardinals do it, I've seen the Los Angeles Dodgers do it. Everybody's excited."

Worth noting

Top catching prospect Travis d'Arnaud was cleared to begin a running progression program after an examination Monday at the Hospital for Special Surgery in Manhattan. d'Arnaud, who fractured a bone in his left foot in April, was cleared to begin limited workouts without running earlier this month.

• As expected, Atchison will join the Mets in time for Tuesday's doubleheader at Turner Field. Atchison, who has been on the disabled list since May 14 with a bout of right elbow inflammation, pitched consecutive scoreless innings for Double-A Binghamton over the weekend.

Anthony DiComo is a reporter for MLB.com. Follow him on Twitter @AnthonyDicomo. This story was not subject to the approval of Major League Baseball or its clubs.