NEW BRITAIN, Conn. -- A couple hours before Carlos Beltran would play right field and bat cleanup in St. Louis, another game in a big league career long on accomplishment, Zack Wheeler kept running and touching cones. From the left-field foul line to the first one and back. To the second, a little deeper into the outfield grass, and back. To the third and back, Wheeler ran hard amid the humidity, his damp workout shirt flopping freely outside of his baseball pants. He did this many times.

About this time last summer, Wheeler was far from here. He pitched in San Jose, Calif., the high Class A affiliate of the San Francisco Giants, but then the Giants needed some offense, someone like Beltran. To get that, the New York Mets said, they must relinquish someone like Wheeler. And so they did -- Beltran straight-up for Wheeler.

Wheeler struck out more than a man per inning at Double-A and allowed just two homers. Mike Janes/AP Images

"That was an honor," Wheeler says. "It said a lot about how the Mets look at me, getting just me for him."

Wheeler, 22, has spent the past year living and playing with that narrow gaze, self-aware enough to acknowledge New York and the bulging expectations of him, aware that the Mets got just him for a seven-time All-Star.

"That's in the back of my mind," Wheeler says. "That's why I work hard. I want to live up to those standards and exceed those."

Wheeler props his long 6-foot-4, 185-pound frame up on the top step of the dugout bench, looking out at this mound here, talking about that one at Citi Field. His performance for Double-A Binghamton this year did nothing to quell the excitement of Mets fans, as he struck out 117 batters in 116 innings while allowing just 92 hits and posting a 3.26 ERA. Those numbers earned him a promotion to Triple-A Buffalo, where he will make his first start on Sunday.

Given Wheeler's ability, the numbers will likely look good at Buffalo, and New York will wonder about the return for Beltran. Mets fans just got their first glimpse of Matt Harvey, their other top pitching prospect, and they're asking about Wheeler, too -- his 94- to 98-mph fastball, his power slider, his unbridled potential for dominance. Is he ready for that, for the crush awaiting his arrival?

Despite a four-pitch arsenal so good only few can compare, Wheeler will still struggle through an outing, hanging breaking balls and missing corners, like he did recently in New Britain, not because of his stuff but because his command still plays its own games with him.

"He's improved his command, but he gets in trouble when he gets underneath his pitches a little," said Glenn Abbott, Wheeler's pitching coach at Binghamton.

Wheeler had a 3.3 walks per nine innings at Binghamton, an improvement from his younger years. Abbot will remind him to trust his stuff, because that's the only thing between him and New York now -- consistent command of it all.

"At the big league level, everybody hits fastballs," Abbott said. "Without command of the secondary pitches, you can't get those guys off your fastball."

That's been the thing with Wheeler since the Giants drafted him sixth overall in 2009 out of a Georgia high school. San Francisco restricted Wheeler to three innings or 50 pitches, generally, at low Class A Augusta in 2010. Occasionally they'd allow 85 pitches when he started, but the club held him to 58 2/3 innings that summer, placing priority on intangible growth instead of tangible results. Wheeler, the strong young man and earnest prospect, resisted this, of course. He had more to give, more to prove.

Matt Harvey has gotten off to a great start for the Mets, but many scouts think Wheeler has even more upside. Jennifer Stewart/US Presswire

"He got upset because he didn't want to be babied," said Steve Kline, Wheeler's pitching coach at Augusta. "But we wanted him to focus on the mental side: Studying hitters, watching tape and watching the games closely."

San Jose was effectively Wheeler's launching pad, the place he mixed untouchable nights with inconsistent days and became someone a big league GM could do something with.

"He seemed very inquisitive," said Andy Skeels, Wheeler's manager at San Jose in 2011. "He never struck me as the kind of kid who had anguish from one start to the next."

In 88 innings with San Jose, Wheeler mostly overwhelmed hitters, striking out 98. He'd throw mid-90s fastballs and low-80s curveballs and work on changeups in fastball counts. He might throw a fastball up-and-in only so he could break one off down-and-away on the next pitch. These were unfair things, he did.

Yet, the command. Wheeler walked lots of batters. His 47 free passes happened when his heater wouldn't listen and he lost the feel of a tight breaking ball coming off his fingertips.

"The stuff was always there," Skeels said. "When he was in the zone, he was unhittable. But sometimes he'd go 0-2 to 3-2 and lose a guy. Fastball command, he was still searching for. He'd look like he had it, and then for two or three starts it would disappear."

As Wheeler worked, the Mets traded for him. Bobby Evans, San Francisco's vice president of baseball operations, called Wheeler in San Jose to inform him. Wheeler would soon phone his agent, Al Goetz, then begin patching the personal wounds that come with being young and traded.

"I made some good friends, and I had to leave them and make new ones," Wheeler said. "If you're weak, it can [affect you]. But it's part of baseball, transitions will be made."

Goetz helped with that, giving his young client confidence at a time Wheeler admits can feel uncertain.

"First I tried to get him over the shock of being traded," Goetz said. "It's a harder lesson for a young kid to learn, so I showed him he has more opportunity and told him he wasn't a number of guys who were traded. It was Beltran for Wheeler. He was the guy who made it happen."

Wheeler threw a few innings in High-A St. Lucie after the trade, learning about the Mets just as they learned about his four pitches, his intensity, how he doesn't like to slow down his delivery, which was the Giants' suggestion because his arm drags and his fastball flattens and it makes him, well, hittable.

The Mets were receptive to these things, and that provided Wheeler confidence, which, along with his talent, brings him to Triple-A and the cusp of the big leagues. His fastball and slider can miss bats in the majors today, his curveball flashes plus and the changeup is coming along. He's just waiting on that last bit of command, and even on days when it fails him and cheap runs cross the plate, Wheeler carries this steely confidence. Asked how he's grown since the trade, Wheeler mentions physical adjustments and then the attitude he's always had.

"When people are taking good swings off you, you may have to knock them down once in a while, and I have no problem doing that," Wheeler says. "It's not cocky, just confidence. If you're going to hit me, you have to hit me."

He doesn't say this viciously. It's just the good hardness the trade has left on him, one that will suit Wheeler well sometime next year in New York, one that he says will help him "the next time it happens."

But maybe there won't be a next time. At least not until he's the accomplished big leaguer and a contender calls for pitching, offering a rare prospect, at which point Wheeler will have become everything New York hopes he will be.

Teddy Mitrosilis is an editor for ESPN Insider. He played college baseball at Long Beach (Calif.) City College and the University of North Carolina at Chapel Hill, where he graduated with a degree in journalism. You can follow him on Twitter here.