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04/05/2013 7:41 PM ET

As Marcum battles injury, Mets face uncertainty

NEW YORK -- Perhaps the most troubling aspect of Shaun Marcum's injury is that the Mets have no idea when he might make his debut.

"I wish I did," manager Terry Collins said. "Because it has to do with the nerves, I'm not really sure how to approach it. I haven't really had to deal with something like that before. So we'll just go on what the doctors tell us and see where he is when it's time to resume some throwing."

The Mets on Thursday gave Marcum a diagnosis of nerve inflammation in his neck, administering trigger-point injections to relieve his discomfort. They will re-evaluate him in Florida this weekend, but that does not necessarily mean a return to the mound.

Even once Marcum does begin pitching, he must build his arm strength back to Major League levels. Because the right-hander has not even completed a bullpen session over the last two weeks, that could take significant time.

"It's all about being able to get his arm up to a consistent release point," Collins said. "If the nerves are flaring up again, he's going to have a tough time doing it, which is going to cause some discomfort. Until a few days from now, we're not really sure where we're at."

In the interim, Aaron Laffey will pitch Sunday, with a chance to stick in the rotation depending on his performance.

Collins gives athletic Valdespin chance in outfield

NEW YORK -- Continuing to seek outfield answers, Mets manager Terry Collins gave Jordany Valdespin his first start of the season Friday, leading him off and slotting him in center.

A natural second baseman, Valdespin began learning the outfield last spring and has played it sporadically over the past year, including a few dozen appearances at all three outfield positions in the Majors. Part of his daily routine includes tracking fly balls during batting practice, and any defensive improvement he displays in the near future could affect his playing time going forward.

"We'll find out," Collins said of Valdespin's outfield chops. "We won't know until we run him out there a few times and see how he does. But he's so athletic, there's no reason why he can't make the adjustment. And if he's going to make a difference with the bat in our lineup, we've got to get him in there to find that out."

Valdespin's bat is what most intrigues the Mets. Though Collins indicated earlier this week that Collin Cowgill, who hit a grand slam on Opening Day, would play nearly every day in center field, Cowgill sat Friday in favor of Valdespin. With Collins hoping to give Kirk Nieuwenhuis and Mike Baxter starts this weekend and the Marlins scheduled to throw three right-handed pitchers, it is possible that Cowgill could sit again.

Cowgill's absence Friday left the Mets with a hole atop the lineup, which Valdespin was happy to fill.

"He brings the same things that Collin Cowgill does," Collins said of the leadoff position. "They make a bad pitch, it's 1-0. He gets on the bases, he scores runs, he can steal bases. If you have him in your lineup, that's probably where he needs to be."

Davis proactive in working his way out of slump

NEW YORK -- This time, the Mets are being a bit more proactive with Ike Davis' struggles at the plate.

Manager Terry Collins addressed the first baseman's early-season woes after Thursday's game, talking to the slugger about his 1-for-12 start. A day later, Davis was the first player to report to an extra batting practice session at Citi Field.

"One thing about him," Collins said, "he's not satisfied with the way he's starting, and he's trying to do something about it."

With most players, a 1-for-12 start would prompt little concern. But Davis knows how quickly slumps can accelerate, after his 0-for-18 to start last season morphed into a .158 average and .507 OPS by mid-June. The last thing Davis wants to do is descend into a similar funk in 2013, now that he is fully healthy for the first time in nearly two years.

"I felt good all spring," Davis said. "I'll be fine."

Wheeler fights butterflies in Las Vegas debut

NEW YORK -- With so many clashing opinions surrounding the Mets' decision to start top pitching prospect Zack Wheeler in Triple-A Las Vegas, Wheeler could have added fuel to the debate by dominating in his Vegas debut.

Instead, Wheeler needed 86 pitches to record 10 outs Thursday, walking three batters and throwing a wild pitch. He acknowledged afterward that he was "maybe just a tad nervous."

"I was a little quick," Wheeler said. "My delivery, I was pushing the ball because I was so out in front of myself, instead of staying back and finishing through the pitch."

How Wheeler copes with the hitter-friendly conditions in Vegas will determine how quickly he can make his Mets debut. Matt Harvey, who was in Wheeler's exact position this time last year, struggled with consistency early at Triple-A and did not debut until late July.

"You've definitely got to keep your mind here," Wheeler said. "That's where you're at. You're playing here with all your buddies and you're trying to win, trying to get better every time you go out there."

The Mets' top overall prospect, Travis d'Arnaud, had a better go of it in Thursday's Las Vegas opener, finishing 2-for-3 with two doubles, two walks, four runs scored and one RBI.

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.