The Red Sox currently are conducting their annual Rookie Development Program. The program typically includes some of the top prospects in the organization who the club believes could make their big league debuts in a 12- to 18-month time frame. Over the course of two weeks, the Sox will work to prepare the group of prospects for a potential call-up, giving the group an opportunity to work with members of the major league coaching staff, to work on strength and conditioning as well as fundamentals, and a chance to become familiar with such details as the layout of the clubhouse at Fenway Park.

Over the duration of the program, WEEI.com will profile some of the prospects taking part in the Rookie Development Program. Today: prospect Casey Kelly, the 2008 first-round draft pick who, after splitting 2009 between the mound and shortstop, decided in concert with the team in December to commit to pitching on a full-time basis.

It should have been the stuff of immense frustration. In late September, Royals pitcher Zack Greinke kept splashing zeros on the scoreboard against the Red Sox, making his opponents seem helpless. Yet for some Red Sox officials, the performance was intoxicating.

It was not merely the act of watching a masterpiece, though that had its appeal. Greinke was delivering a virtuoso performance, carving up the strike zone with a sophisticated array of pitches: high-90s heat, a Bugs Bunny curveball, a devastating slider and, for good measure, a changeup that further disrupted the timing of the Sox.

Yet somehow, the fact that Greinke permitted two hits in six shutout innings seemed filled with promise for the Sox, for one simple reason. It was the sort of performance, multiple members of the organization daydreamed, that Casey Kelly might deliver in the major leagues one day.

Kelly, in fact, views Greinke as something of a model for his own work on the mound. Like Kelly, the Royals ace exhibited tremendous athleticism in high school both as a pitcher and a position player (though whereas Kelly was a shortstop, Greinke was an outfielder).

Both Florida natives were so dominant on the mound, however, that their careers inevitably veered in that direction. Now, Kelly finds plenty to admire — and imitate — in Greinke’s game.

“I just like the way he pitches,” Kelly said. “He’s an athlete on the mound. That’s something I want to take away from how he pitches, and a Cy Young winner is not a bad guy to be watching.

“He’s got a nice fluid motion. That’s something that I try to do in my motion, also. His ability to throw strikes, to throw pitches in any count that he wants to, is pretty amazing. I can only hope that he gets to the level that he’s at. That’s what I’m working on now, trying to develop my pitches in different counts.”

It would be wrong and unfair to suggest that Kelly at this early stage of his career can or should near Greinke’s success. Greinke, of course, is much more advanced and refined than the Sox’ top pitching prospect; that was also true of Greinke when he was 19 and exhibited singular dominance in the minors. Now, almost no one in the majors has the combination of command and devastating stuff as Greinke.

Even so, the fact that Kelly offers even faint echoes of the Kansas City ace speaks volumes about why he is so highly regarded. And multiple talent evaluators who have watched both pitchers suggest that there is some hint of Greinke in the Sox minor leaguer, particularly in Kelly’s ability to repeat his delivery and release points. Those skills, in turn, allow Kely to manipulate the baseball and locate multiple pitches on both sides of the plate.

Those attributes were apparent in Kelly’s startling first full professional season, at least on the mound. He amassed a 6-1 record and 1.12 ERA while striking out 39 and walking just nine for Single-A Greenville. Promoted after nine starts to High-A Salem, Kelly continued to deliver the goods.

Though he had a 1-4 with a 3.03 ERA in Salem, in some respects, he was more impressive. He gave up no hits or one hit in three of his first six starts in High A. He improved his strikeout-to-walk rate and lowered his walks per nine innings, a sign of his fearlessness once promoted to a higher level.

To put that High-A performance in context, Kelly and Royals prospect Mike Montgomery became the first Carolina League pitchers to record an ERA of 3.09 or better at the age of 19 (min. 46 innings) since Greinke went 11-1 with a 1.14 ERA at the level in 2003.

Kelly’s build and performance have also earned some comparisons to Rick Porcello, another powerful, athletic right-hander. Porcello had a 2.66 ERA as a 19-year-old in 2008 in the High-A Florida State League before jumping straight to the majors and delivering a tremendous rookie season (14-9, 3.96 ERA) for the Tigers in 2009. Others suggested that his advanced command bore resemblance to a young Brad Radke, the longtime Twins ace.

That Kelly can exhibit similarities to that accomplished group says a great deal about why the organization is so excited for the 2008 first-round pick to commit full-time to pitching. He will define his own career path, of course, but the initial impressions have been nothing but positive.

In 2009, Kelly demonstrated a repertoire that was extremely advanced for his age and experience. He showed above-average command of a low-90s four-seam fastball and a two-seamer, using both effectively to both sides of the plate. He is similarly advanced in his ability to command his curve and changeup, both of which project as potential plus pitches.

“His curve, he hasn’t had to go to it much because he usually has them swinging early in the count,” Salem pitching coach Dick Such said during the season. “But he’s got an exceptional curveball. The first time I saw it, these guys went crazy when I said, ‘Well, hello darling.’

“Now I drop it on him when he throws an outstanding changeup. That’s been an exceptional pitch for him here, because it looks like his fastball but he’s got such a good feel for it, that’s one of the reasons he hasn’t had to depend on his breaking ball because his change has been so outstanding.”

But as much as Kelly has impressed with the feel for his pitches, it is, more broadly, his feel for the game and his ability to know exactly what he is doing that has made an even greater impression on pitching coaches in the organization. He has an advanced understanding of execution, and has demonstrated remarkable concentration and focus on the mound.

That was most apparent in his second start with Salem, against Orioles top prospect Brian Matusz. Rain delays pushed the second game of a double-header to a starting time after midnight. Yet Kelly maintained his concentration and was locked in when he took the mound. He executed his gameplan — quite literally — to perfection over six innings when he didn’t permit a baserunner.

“He gets it. He gets it,” Sox pitching coach John Farrell said. “When you talk about concepts or you talk about situations on the mound, in-game situations, there’s not a bewildered look. There’s a response as he interprets it. He understands the conversation as you’re trying to describe the situation, or the feel of a pitch as you’re trying to execute it properly.

“His ability to communicate what his thought process is at times, whether a pre-pitch routine or what he does leading up to a game, is very genuine. It’s very relaxed. For someone who’s 20 years old, it’s pretty darn advanced.”

Those talent evaluators who believe that Kelly has been overhyped on the mound suggest that his fastball — currently a pitch in the low-90s — lacks the power of a top-of-the-rotation starter. There are those who believe that unless his fastball plays up, he may be more likely to end up being a back-end starter.

But, given that Kelly is 20 and the mental aptitude he has shown, the idea that he will continue to improve and develop is well within reason. Kelly clearly added muscle over the offseason to fill out his frame (“You always want to come in and show you’re in good condition and you’re always trying to earn a job,” Kelly said). He now has a powerful pitcher’s build that makes it easy to project a bump in velocity and overall stuff.

That said, Kelly has been around the game for long enough — his whole life, really, as the son of former major leaguer Pat Kelly, who has worked in player development for several teams — to understand that projectability does not guarantee results. The 20-year-old has thrown less than 100 innings as a pro. He must accomplish more before he can rightly think about the majors, let alone being the next Greinke.

But Kelly has shown enough in his limited exposure to professional pitching that he will be in major league camp with the Red Sox in spring training, and he will compete for a spot in the rotation of Double-A Portland. The Sox believe he has the capability to remain on the fast track. That is especially true now that he is committed solely to pitching, having concluded the one-year experiment of life split between pitching and playing shortstop.

“The criteria that we hold in terms of progressing players through the system, especially a starting pitcher, which is repeating your deliver, throwing your fastball to both sides of the plate and throwing your secondary pitches for strikes, Casey demonstrates a lot of those things already,” farm director Mike Hazen said. “We feel pretty good that, if everything continues to progress, he could move pretty quickly.”

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