Top prospect Wheeler ready to make big league debut for Mets

The Mets are hoping Zack Wheeler can join Matt Harvey as a mainstay atop their rotation for years to come. (Julio Cortez/AP) Tuesday will be a red-letter day

The Mets are hoping Zack Wheeler can join Matt Harvey as a mainstay atop their rotation for years to come. (Julio Cortez/AP)

Tuesday will be a red-letter day for prospect hounds. Not only is Wil Myers getting his long-overdue call-up to the Rays but Zack Wheeler will make his debut for the Mets, starting the nightcap of a day-night doubleheader against the Braves in Atlanta.

The sixth pick of the 2009 draft by the Giants out of a Dallas, Ga., high school, Wheeler was acquired by the Mets on July 28, 2011 in exchange for Carlos Beltran, a player the team didn't intent to re-sign anyway and who spent just two months with San Francisco. Wheeler, a 23-year-old righty, is widely considered one of the game's top prospects, having been ranked fifth by Baseball Prospectus, 11th by Baseball America and 13th by ESPN's Keith Law before the season.

Wheeler has a 3.93 ERA at Triple-A Las Vegas, but he's pitching half his games in one of the toughest parks of a notoriously hitter-friendly league. The small-sample splits show that he has a 5.12 ERA at home while allowing 2.0 homers per nine, while on the road he's at 2.89 with 0.5 homers per nine. More importantly, he's striking out 9.6 per nine in Triple-A, helping to offset high walk and homer rates (3.5 and 1.2 per nine); his groundball rate is just 42 percent, down from last year's 48 percent, which has been a bit of a problem in the thin air. Under more gravity-friendly conditions last year he posted a 3.26 ERA in 149 innings split between Double-A Binghamton and Triple-A Buffalo, whiffing 8.9 per nine with 3.6 walks and 0.2 homers.

Prospects are about more than the numbers, though, and there's a whole lot to like about Wheeler, starting with his lanky 6-foot-4, 185-pound build and his four-pitch mix, headlined by a mid-90s fastball that can touch 98 mph. His curve is considered to be a true plus pitch as well, and he adds an above-average slider and a changeup that's at least average. At the very least, he projects as a frontline starter. Wrote Law, "[H]e has a chance for three 60-grade pitches or better on the scouting report -- along with a durable build and the control to pitch in the majors right away, which would make him no worse than a solid No. 2." Parks was more focused on the upside, writing, "He has legit top-of-the-rotation potential, which means he could win 20-plus games and strikeout 200-plus hitters."

That's not to say that Wheeler is an entirely finished product, but then few pitchers — even blue-chippers — are as of their major league debuts. Parks noted that while Wheeler has sharp command of his secondary pitches, the same can't be said of his fastball. Law described Wheeler's changeup as "probably too hard to be truly effective," suggesting that he either needs to take a bit of velocity off of it or adjust his grip to give it more movement. His delivery still has some rough edges that occasionally cause him to elevate his pitches, hence the lower groundball rate.

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Even with those caveats, that's a pretty exciting prospect, particularly when paired with the Mets' current phenom, Matt Harvey, who through 24 major league starts since last July 26 has a 2.30 ERA with 9.9 strikeouts per nine, not to mention a case that he should be starting this year's All-Star Game in Queens. While most scouts and prospect evaluators agreed that Harvey had the makings of a good major league pitcher heading into last year, few saw him as an ace in the making; BP's Kevin Goldstein (who now works for the Astros) placed him one notch ahead of Wheeler in his Mets Top 11 Prospects list, calling him, "At least a number-three starter with a good chance of become a number-two with some refinements." Harvey's improved slider has turned him into a dominant force, again a reminder that pitchers debuting at the major league level aren't done with their development.

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Still, it's worth tempering initial expectations given the mixed bag of results that a trio of blue-chip pitchers have offered in their recent debuts:

• Kevin Gausman, Orioles. Ranked 26th on both Baseball America's and ESPN's list coming into the year after being taken with the fourth pick of last year's draft, Gausman debuted on May 23 with just 61 1/3 minor league innings under his belt. He allowed four runs in five innings against the Blue Jays, showing off excellent stuff in the early going but yielding a two-out, two-run homer to J.P. Arencibia that sullied his final line. In five starts, he has a 7.66 ERA, with impressive showings against the Tigers and Red Sox but poundings by the Nationals and Rays. He was optioned back to Triple-A on June 13, despite allowing just two runs in 5 1/3 innings against Boston.

• Michael Wacha, Cardinals. The 19th pick of last year's draft out of Texas A&M, Wacha ranked 76th on Baseball America's list on the strength of just 21 professional innings. He pitched to a 2.05 ERA at Triple-A despite striking out just 5.8 per nine, then got the call to join the big club in the wake of a handful of injuries. He impressed with a seven-inning, six-strikeout, one-run debut against the Royals on May 30, was pounded by the Diamondbacks in his next start, but pitched well against the Mets last week; through three outings, he has a 4.58 ERA and 7.1 strikeouts per nine.

• Gerrit Cole, Pirates. The overall number one pick of the 2011 draft was last week's sweetheart, and he acquitted himself well in his debut, holding the Giants to two runs in 6 1/3 innings. On Sunday against the Dodgers, he came within one out of a quality start, yielding three runs in 5 2/3 innings. He has a 3.76 ERA so far, but just three strikeouts in 12 innings, mirroring the concerns that despite top-shelf stuff, he's not missing enough bats.

Wheeler's debut will have as much buildup as those three, if not more. Not only will he be pitching some 30 miles from where he grew up, he'll have an audience that includes Mets general manager Sandy Alderson and chief operating officer Jeff Wilpon, both of whom will make the trip to Atlanta. He'll be facing a team that at the moment is tied for the league's third-best record (41-28), owning the majors' largest division lead (6 1/2 games) and averaging 4.32 runs per game (sixth in the league). No pressure, right? The good news is that the Braves' bats are in a bit of a slump, averaging just 3.73 runs per game this month, and scoring more than three in just three of their last 10 games; the expectation is that the lineup will be a bit diluted by the doubleheader.

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