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The New York Mets shook up their roster following their most recent defeat. They hope the atmosphere change can lead to some success on Tuesday evening when they begin a three-game set with the St. Louis Cardinals.

The Mets have lost six of seven since sweeping the New York Yankees in four games at the tail end of May. Five of those defeats have come to the Miami Marlins, owners of the worst record in baseball.

That distinction could soon belong to the Mets given their current direction. They are 12 games under .500 at 23-35 and are coming off a pair of losses that seem to have caused things to boil over.

New York lost a 2-1 contest to Miami on Saturday, a game that took 20 innings to complete, and then saw the Marlins plate four runs in the 10th frame of Sunday's finale en route to an 8-4 setback.

Mets manager Terry Collins was asked afterwards on whether this was the team's lowest point of the season.

"It's certainly pretty close," Collins said. "This is when you reach down and find out who belongs here and who doesn't."

For now, the Mets decided that first baseman Ike Davis, outfielder Mike Baxter and relief pitcher Robert Carson do not belong, demoting the trio to Triple-A Las Vegas. Expected to be a source of power in New York's lineup, Davis was hitting just .161 on the season after an 0-for-3 performance on Sunday.

Joining the Mets from Triple-A were outfielder Collin Cowgill, infielder Josh Satin and left-handed reliever Josh Edgin.

Perhaps the new players can help alter the tough luck Jeremy Hefner has experienced this season. The right-hander aims for just his second victory of the season in tonight's opener.

Hefner went 0-5 through his first 10 starts of the season, with the Mets losing all 10 games. The hurler finally broke through with a victory over the Yankees on May 29, but his tough luck returned last time out on Tuesday in Washington.

The 27-year-old retired 14 of the first 15 hitters faced and yielded one run over seven innings while striking out seven. He was in line for the win before closer Bobby Parnell blew a save chance in a 3-2 loss.

"It's a little tough, but I'll take Bobby any day," said Hefner, who is 1-5 on the year with a 4.36 earned run average. "He's been great all year, and today he just had a bad day."

Hefner faced the Cardinals for the first time in his career on May 13 in St. Louis and did not factor into a 6-3 setback. He was charged with three runs over six innings as well as a season-high four walks.

St. Louis won three of four in that series from May 13-16 and has taken six of the previous eight encounters overall.

The Cardinals are coming off a series victory over the Cincinnati Reds, winning Sunday's finale 11-4 thanks to a seven-run 10th inning. Matt Holliday highlighted the big frame with his fifth career grand slam, while Carlos Beltran had a solo homer and drove in two runs.

With the Reds winning on Monday against the Chicago Cubs, the Cardinals own a 3 1/2-game edge over Cincinnati for first place in the NL Central.

"I think every time we play the Reds this year it is a big series," Holliday said. "Because ultimately it looks like we're both going to be battling for the division."

Matt Carpenter drove in three runs on Sunday and is batting .418 over an 18- game hitting streak, while David Freese has a .375 average and 16 RBI over his 19-game hitting streak.

The duo will look to get 21-year-old Michael Wacha his first MLB victory tonight.

The 19th overall pick of the 2012 draft, Wacha had an outstanding big-league debut on May 30, holding the Kansas City Royals to a run on two hits over seven innings of a no-decision. However, the righty was not as sharp last time out, tagged for six runs on 10 hits and a walk in 4 2/3 frames of work versus the Arizona Diamondbacks on Tuesday. Wacha, though, got another no-decision while his ERA moved from 1.29 to 5.40.

The Texas A&M product will make his first career road start tonight.