Twins center fielder Byron Buxton, No. 1 on the MLBPipeline.com Top 100 Prospects list, isn't going anywhere. The Cardinals' Oscar Taveras (No. 3) definitely will stay in the outfield, too, though he'll probably shift from center to right in the long run.
But shortstops Xander Bogaerts (No. 2, Red Sox) and Carlos Correa (No. 8, Astros) have a good chance to outgrow their current positions and slide over to third base once they fill out their tall frames. Twins slugger Miguel Sano (No. 4) is huge and isn't finished adding strength, which could push him from third base to first base or an outfield corner. Shortstop Javier Baez (No. 7, Cubs) and third baseman Kris Bryant (No. 9, Cubs) are capable defenders, but the presence of shortstop Starlin Castro in Chicago could shift Baez to the hot corner and Bryant to an outfield corner.
Which of these überprospects is most likely to move? Jonathan Mayo believes it's Baez, mainly in deference to Castro, who has $49 million remaining on a contract that runs through 2019. I believe it's Sano, who ultimately will be too big to play third base.
When he signed for $3.15 million as the top talent on the international amateur market in 2009, Sano was a 16-year-old who already stood 6-foot-3 and weighed 195 pounds. A year later, he weighed 230 pounds. Currently he's listed at 6-foot-4 and 235 pounds -- in reality he's closer to 250 -- and he's only 20.
To his credit, Sano has worked diligently on his defense. Though he's the top power-hitting prospect in the Minor Leagues and it will be his bat that carries him to stardom, he's trying to become the best third baseman he can be.
Sano's cannon arm grades as well above average and is more than strong enough for the hot corner. He's reasonably athletic for his size and while he's not especially quick, he has some lateral range. His footwork has gotten better, and his hands and instincts are OK. In a sign of progress, he reduced his errors from 42 in 125 games in 2012 to 23 in 120 contests last year.
Though Sano can become an adequate third baseman, that's his ceiling as far as defense goes. He's already a massive human being who continues to fill out, and as he gets bigger, he's going to lose some speed and cover less ground. And that will necessitate a move to a less-challenging position -- either first base or a corner-outfield spot.
Sano almost certainly will break into the Major Leagues as a third baseman, pushing Trevor Plouffe to a utility role when he comes up at the end of this season or early in the next. But among the game's top prospects, Sano is the least suited for his current position. The good news is that his power will play wherever he winds up.