Jordan Sheffield, one of the top high school arms in the Draft class of 2013, will undergo Tommy John surgery on Thursday morning, MLB.com has learned.

Dr. James Andrews will perform the surgery on the talented right-hander. Sheffield, the nephew of former big leaguer Gary Sheffield, was ranked No. 47 on MLB.com's most recent ranking of the Top 50 Draft prospects, but this turn of events leaves his immediate future up in the air.

"I haven't gotten to speak with him, but talking to his brother and dad, he was upset, obviously, at first," said Brad White, Sheffield's coach at Tullahoma (Tenn.) High School. "Obviously, his high school career is over. I know he's thinking, 'I've got the best man in the business doing the surgery; that's the best I can hope for. And I'll have a new arm when this is over with.'"

Sheffield hasn't pitched since March 12, when he exited a start after 73 pitches because of tightness in his forearm. He rested and rehabbed the arm, acting as the team's designated hitter in the interim. He didn't even return to his normal non-pitching position, shortstop, until Tullahoma's opening game at the National High School Invitational at the USA Baseball National Training Complex on March 27.

Things appeared headed in the right direction, and Sheffield was slated to pitch the following day, but when he was warming up in the bullpen, he told White that something didn't feel right and was scratched. He played first base for the remainder of the tournament.

Sheffield went for an MRI after the tournament, with mixed evaluations. According to White, one doctor said there didn't appear to be any structural damage, whereas a second doctor detected a tear. Based on that, the decision was made to see Dr. Andrews. Sheffield visited the renowned surgeon on Wednesday morning and was scheduled for surgery.

"Jordan, when he's challenged, he can really step up," said White, who used his senior star at DH for a couple of games before taking him out of the lineup a few days before his appointment with Dr. Andrews. "I can't think of a bigger challenge than this for a 17-year-old [pitcher]. If he faces this like he has every other challenge, then I like his chances."

What happens post-surgery remains to be seen. Sheffield has, when healthy, what White calls one of the "top five electric arms" in the Draft, with the ability to hit the upper 90s with his fastball and a very sharp breaking ball. He's not the biggest pitcher in the world, which might have made some teams shy away, if his strong commitment to Vanderbilt didn't do so before that.

"I think most people thought he was going to be a very difficult sign to begin with because he was committed to Vanderbilt," one scouting director said. "He's a little more in the [mold of] Sonny Gray [a Tennessee high school prospect who went to Vanderbilt and became a first-round pick of the A's in 2011]. This kind of sealed the kid's fate, with a capped Draft and a commitment to Vanderbilt. I can't imagine someone would go real big unless he wants to sign, and I don't think that's the case.

"If I had to bet, he'll red-shirt, and next September he'll be at Vanderbilt."

There is precedent for Draft talent undergoing Tommy John surgery and still ending up as top Draft talent. A year ago, Lucas Giolito was the most exciting prep arm in the class, but he missed nearly all of his senior season because of elbow trouble. The Nationals rolled the dice and took him No. 16 overall, and the big right-hander went under the knife at the end of August. It's possible Sheffield could follow that route.

"The case everyone is keeping their eye on is Lucas Giolito," White said. "He was in a very similar situation as Jordan [is now]. Maybe he'll be like Giolito but have a five-month head start on him."

"Giolito was much more of a consensus player," the scouting director countered. "I thought that was a great pick by Washington. Rehabbing the kid for a year, you couldn't get a guy that good last year. Sheffield, he's a smaller guy with a big arm.

"People want to pooh-pooh that surgery, but it's still a major surgery. You're out a year. It's not like you sprained your ankle, though it's usually pretty successful."

If Giolito isn't the right model to follow, perhaps Sheffield can look at a Tullahoma alum. Dewon Brazelton underwent Tommy John surgery while a sophomore, then attended Middle Tennessee State and was the No. 3 overall pick in the 2001 Draft. Yes, his big league career didn't go as planned, but going from elbow surgery to top Draft pick has to be deemed a success.

"It will be interesting to see what happens there," said White, who, ironically, was preparing for a game at Vanderbilt University and found out about the surgery alongside Vandy coach Tim Corbin. "It'll be a good case study. A lot of teams saw him in the offseason [at his best]. It'll be neat to see if someone decides to take the gamble and try to sign him away from his scholarship at Vanderbilt.

"Coach Corbin and I were in shock -- his present coach and possibly his future coach right there."