Manny Banuelos wasn't just the talk of Yankees camp in the spring of 2011. He was one of the biggest stories in the Grapefruit League. Though he had pitched just three games above Class A, he looked capable of joining New York's rotation, if not on Opening Day then soon thereafter.

Banuelos didn't allow a run in his first four outings, including in a scoreless start against the Red Sox the day after he celebrated his 20th birthday. He showed flashes of three plus-pitches and Mariano Rivera tabbed him the best pitching prospect he had ever seen.

"I like everything about him," Rivera told ESPNNewYork.com. "The makeup and how he keeps his composure. I notice situations and how you react in situations. Where you make your pitches in tough situations, where you spot your pitches, he has the ability to do that."

But Banuelos never took the mound for the Yankees in 2011. Or 2012 or 2013 or 2014, for that matter. And he likely never will now since New York traded him to the Braves for David Carpenter and Chasen Shreve on New Year's Day.

For someone who looked like he would be their next homegrown All-Star left-hander, following in the footsteps of Andy Pettitte and possessing better pure stuff, the Yankees got a pair of useful bullpen arms. Based on what Banuelos' ceiling once appeared to be, they definitely sold low. But based on what he has gone through the last three seasons, New York preferred the certainty of two middle relievers who have pitched in the big leagues over what Banuelos might become.

The biggest setback in Banuelos' development has been an elbow injury that cost him most of 2012 and, after he had Tommy John surgery, all of '13. In addition, while he has shown premium stuff and quality command in the past, he rarely has displayed both at the same time.

When Banuelos signed in 2008 as part of a four-player package from Mexico that cost the Yankees $450,000, he stood out more for his poise and pitchability than his repertoire. His stuff took off in 2010, with his fastball jumping from the high 80s to the low 90s and reaching as high as 95 mph, his curveball adding power and depth and his changeup confounding hitters with its fade and sink. His strikeout rate rose from 8.5 per nine innings in his first two seasons to 11.8 in his third, but his walk rate also increased from 2.4 to 3.5.

Banuelos continued to show the making of three swing-and-miss offerings in 2011 while reaching Triple-A, though upper-level hitters often waited him out. His strikeout rate dipped to 8.7 while his walk rate continued to soar to 4.9. He returned to Triple-A in '12 and made just six starts before getting shut down for the season and having his elbow reconstructed in October.

The Yankees eased Banuelos back in 2014, limiting him to 76 2/3 innings over 26 games (25 starts). His fastball velocity returned for the most part, averaging 92 mph and topping out at 95, but his secondary pitches weren't as sharp as they had been and he continued to work from behind in the count too often. He added a slider/cutter to give him a fourth pitch and did show signs of overall progress during instructional league.

So what does the future hold for Banuelos? One scout who saw him at his peak prospect value in 2011 loved his stuff and mound presence, though he thought his lack of size (5-foot-10, 205 pounds) and command would lead him to the bullpen. The scout envisioned him as Rivera's eventual successor at closer, and while that didn't happen, Banuelos ultimately may be best suited for relief.

Banuelos' control and command shortcomings wouldn't be as big a negative if he didn't have to worry about working deep into games as a starter. Coming out of the bullpen also would figure to add velocity to his fastball and help his secondary offerings play up as well. He has yet to prove he had the durability for the rotation, topping 100 innings just once in seven years as a pro.

The Braves will try to see if Banuelos can make it as a starter first. The fifth spot in their rotation is open at the moment, and he'll get an opportunity to audition for it during Spring Training. He'll be 24 this season and his stock isn't nearly as high as it was four years ago, but somewhere in there could be a frontline lefty starter.

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Jim Callis is a contributor to Sports on Earth. He has been covering prospects and the draft since 1988, when he began the first of two long stints at Baseball America. He joined MLB.com and MLBPipeline.com in September 2013. Follow him on Twitter at @jimcallisMLB.