Not finding a true defensive home until reaching the major leagues is nothing new. When it comes to signing amateur players, tools and athleticism rule the day, but there's a scale of relativity that always needs to be accounted for. The best athlete on a high school team plays shortstop, but once you drop that player into professional baseball, he might only be a first baseman. With that in mind, here are five big-name prospects that might end up somewhere different than where they are playing now in the minors:

Dustin Ackley, 2B, MarinersThe second overall pick in the 2009 draft might just be the most interesting defensive case in the minors. He was primarily a first baseman during his college career at North Carolina, but that was because he was recovering from Tommy John surgery and couldn't throw. He's a plus-plus runner with up-the-middle athleticism, and while most teams thought center field was his most logical landing spot, the Mariners' initial play is second base, a position he has no experience at. While he's been struggling with his bat at Double-A this year, scouts say he looks surprisingly comfortable with the glove.

Pedro Alvarez, 3B, PiratesLike Ackley, Alvarez is also a second overall pick (2008) with questions about his ultimate defensive home. Nobody has questions about his bat, but at 6-3, 225 (and probably more than his listed weight) his range at the hot corner is a bit limited, although to his credit his hands and arm are solid. The Pirates kept him out of winter ball in the offseason so he could focus solely on conditioning, but they're likely just holding off the inevitable move to first base. Expect a Jim Thome-like transition where at least the first few big-league years are spent at third.

Jesus Montero, C, YankeesMontero is one of the best hitters in the minors, period. But if he can't stick at catcher, it's difficult figuring out where his future lies for the Yankees other than as a massive trade chip, as first base is Montero's only other option, and Mark Teixeira is signed more than halfway into the decade. To his credit, Montero wants to be a catcher, and he's putting the time in to improve, but he's still big and slow behind the plate, and he's thrown out just one of 14 base stealers this year at Triple-A. Few think he can stick there, but many think he could help in the big leagues this year, and it's not like Nick Johnson is doing much at designated hitter.

Miguel Sano, SS, TwinsSano was the biggest prize in last year's international market, and the Twins surprised many as the winner with a $3.15-million bonus. He's listed as a shortstop, but one will notice that few players signed at 16-year-olds are ever listed as anything but shortstops or outfielders. At 6-3 and 200 pounds, Sano has almost already grown out of shortstop, and he could make his debut later this year at third base, with some thinking that right field could be his final destination.

Josh Vitters, 3B, CubsThe third overall pick in 2007, Vitters is in some ways a younger version of Alvarez. Scouts are mixed on his defense. Some see a solid-but-unspectacular defender at third base that could project as at least acceptable as a big-leaguer, while others think he's destined for a move to first base or the outfield. There is a lesson here, as from years of experience I've learned that if there are even whispers of a defensive move for a prospect, they tend to happen, as the bar at the big-league level really is that high.

Five More Too Keep An Eye On

Tim Beckham, SS, RaysThe top pick in the 2008 draft is in much better shape this spring, but some scouts wonder if his thick build isn't better suited for third; either way, he needs to start hitting.

Hank Conger, C, AngelsHe has never caught more than 100 games in a season, and he's below average behind the plate due to both a lack of development and a huge, round frame. He doesn't have another place to play, and Angels manager Mike Scioscia insists on good defense (see his use of Jeff Mathis over Mike Napoli this season before Mathis was injured).

Wilmer Flores, SS, MetsThe 18-year-old is the best offensive prospect in the Mets' system, but nobody thinks he can stay at shortstop, as he's big and just getting bigger. Third base is the next stop, but that could just be temporary, as many see him as a bat-first corner outfielder down the road.

Todd Frazier, Everything, RedsThe 2007 first-round pick has played every position except center field and catcher as a pro, and is currently splitting time between first, third, and left field at Triple-A. In the end, the versatility could prove to be a good thing, as he can fill many potential needs.

Wil Myers, C, RoyalsKansas City shelled out $2 million for Myers as a third-round pick last summer, and for the most part, they were paying for a bat with the hope that his desire to catch would lead to potential superstardom. He has a strong arm and the tools to be a good catcher, but his lack of experience behind the plate has shown so far at Low-A Burlington, as he's currently second in the league with four passed balls in just 12 games.

A version of this story originally appeared on ESPN Insider Insider.

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With all the talk of how poorly guys like Vitters and Alvarez play the field, how does a guy like Edwin Encarnacion make it to the big leagues there?
Folks used to say the same exact things about Aramis Ramirez as they now do about Pedro Alvarez (barely adequate range, big frame likely to get bigger, strong but inconsistent arm)... so many years later, Aramis is still playing 3b. I think it's very possible Alvarez could still be at 3b until his free agent years.
how much of a difference exists between montero and someone like posada or victor martinez when it comes to catching defense and such? if the difference isn't huge, like 10 runs a season, i think the yankees will be very happy with him as a catcher, even if he is a bad one.
If Montero makes 100 starts at catcher in the majors for his career, I'll eat a Yankees cap.