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05/15/2013 8:22 PM ET

Niese makes adjustments, hopes for results

ST. LOUIS -- The worst two-start stretch of Jon Niese's career forced the Mets' left-hander to look in the mirror. Literally.

Niese spent this week refining his mechanics in front of a weight room mirror, trying to keep his body tall and on a straight line. Those were the issues that he considered crucial to his recent struggles, resulting in 15 runs over his last two starts.

"Whenever I had free time, I just stepped in front of a mirror and went through my mechanics, and made sure everything's on line," Niese said. "I can feel when it's right."

Though Niese will not know for certain whether the problem is fixed until he takes the mound Thursday at Busch Stadium, he considered his between-starts bullpen session his best of the year. In an attempt to change his recent fortunes, Niese threw more max-effort pitches in the session than usual.

He insisted that he felt completely healthy doing it, no longer experiencing the back soreness that plagued him earlier this month.

"It was just good to get a good workout in, being able to cut loose in the bullpen," he said. "I've been cutting pitches off, short-arming it. It felt good just to kind of let the arm go."

Wheeler to miss just one start; Mets relieved

ST. LOUIS -- As the Mets hoped and expected, top pitching prospect Zack Wheeler has no structural damage in his right arm, and will miss only one start for Triple-A Las Vegas.

"Feeling good and ready to get going again," Wheeler tweeted. "Thanks for all the kind words and concerns."

An MRI Wednesday in New York revealed only mild inflammation of the AC joint in Wheeler's shoulder. The right-hander received a cortisone shot and will skip his next start, but nothing beyond that.

"I'm very happy and relieved -- very relieved," manager Terry Collins said. "I was certainly very worried. Any time you have a kid with that time of talent and you talk about arm stuff -- especially when you talk about the shoulder area -- it scares you to death. So it's great news."

Assistant general manager John Ricco said that Wheeler's timetable to reach the big leagues "hasn't changed," meaning he should debut sometime after next month's estimated Super 2 arbitration cutoff. Because the Mets play five games in four days in Atlanta from June 17-20, that is the most logical week for Wheeler's first start.

But the timetable depends upon Wheeler's own progress. The right-hander has gone 2-0 with a 1.35 ERA, 19 strikeouts and three walks over his last three starts, after opening the year 0-1 with a 5.79 ERA, 28 strikeouts and 19 walks in five outings.

"He's progressing," Ricco said. "I think the results have shown that. I don't think there's any one magic thing that we're looking for, but we talk on a start-by-start basis. We'll make a decision based on when we think the time is right."

Streaky Murphy going up after busting slump

ST. LOUIS -- In the sixth inning of last Sunday's game against the Pirates, Daniel Murphy swung at a Vin Mazzaro breaking ball and missed by nearly a foot. He struck out, leaving home plate hitless for a 17th straight at-bat while looking utterly lost at the plate.

But Murphy doubled in his next plate appearance, snapping his 0-for-17 funk and keying a 7-for-9 renaissance, which has included two doubles, two RBIs and two runs scored.

In that fashion, Murphy furthered his reputation as one of the streakiest hitters in baseball. Consider his month-by-month slash lines (batting average, on-base percentage and slugging) from last May through September:

May: .303/.361/.384
June: .240/.253/.427
July: .360/.380/.528
August: .225/.286/.270
September: .337/.381/.483

Wildly streaky from month to month, Murphy nonetheless made good on manager Terry Collins' assertion that his typical statistics -- most notably a batting average around .300 -- would be there at the end of the season. Collins has recycled that line of thinking this year, with Murphy riding multiple early-season peaks and valleys.

"It's tough to explain," Murphy said. "Once you start feeling good and then you have some success for it, it just lends to more peace and less anxiety."

The opposite, Murphy said, is also true. But by ignoring the short-term fluctuations of his season, he believes he can achieve his long-term objectives.

"Obviously you want to be as productive as possible every day, but you're going to go through stretches," he said. "I think the biggest thing is trying not to look at the whole picture. You try to narrow it down not even to at-bats, but to individual pitches. Then the goals become a little more attainable."

Collins affirms his respect for Mets fans

ST. LOUIS -- Mets manager Terry Collins said he regretted his Tuesday comments regarding Jordany Valdespin, particularly his admonition that he does not "answer to fans."

"Of course I regret the choice of words," Collins said Wednesday. "I certainly respect the New York fans. They're the most knowledgeable fans I've ever been around. They know the game. They know the people.

"You know, I'm a human being. I used a bad choice of words. But I'm also frustrated. Here we are -- we're scuffling, scuffling. There's one topic to talk about. And I understand that we're not playing good, so that's the story. I'm aware of that. And I'm tired of talking about it. I want to talk about getting better. So that was my fault -- nobody else's fault. I wasn't baited into anything. Once again, I want our fans to understand that I'm working my butt off to get better. Period."

To do that, Collins vowed to remain upbeat, which he admittedly did not do during previous managerial stops in Houston and Anaheim.

"Years ago I let it get to me, because I thought it was a direct reflection of the job I was doing," Collins said. "Right now, I know they've got to play and they've got to be ready. My job is to make sure they stay ready. And the one way to do that is to keep them positive."

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.