Viva El Birdos Cardinals Top Prospects: #7 Magneuris Sierra

Editor's Note: Red Baron has compiled this year's top prospects in three parts, which can be found by clicking on Part I, Part II, and Part III. The post below is a portion of those massive posts, focusing in on a single prospect at a time, which should make a search of any one prospect easier to find. All of our 2016 prospect coverage and write-ups can be found at the Viva El Birdos 2016 Prospects hub.

#7: Magneuris Sierra, OF

2016 Opening Day Age: 19 (turns 20 early April)

2015 Level: Low A Peoria, Short-season Johnson City

Relevant Numbers: 117 wRC+ (JC), 15 SB - 2 CS (JC), 7.9% walk rate (JC)

So, what's so great about this guy?

Magneuris Sierra won the Cardinals' Minor League Player of the Year award in 2014, following a campaign which saw him hit .386/.434/.505 as an eighteen year old in his first season stateside. He was challenged with a promotion to full-season ball to begin 2015, and it...did not go well.

Playing at Peoria, Sierra posted a 33 wRC+, was caught stealing five times against just four successes, and looked completely overmatched at the plate, striking out almost 30% of the time and walking less than 4%. The Cardinals wisely demoted him to short-season ball once those clubs got underway, and Sierra rebounded nicely, putting up solid numbers in the Appy League, though nothing close to his otherworldly 2014.

It will be one of the big storylines in the Cards' minor league system this coming year, watching what Sierra does as he tries full-season ball again. He'll be 20, which is still young for the Midwest League, but not necessarily young for a prospect in the Midwest League. The plate approach looked very advanced his first two years of pro ball, but disintegrated completely facing Low-A opposition, and it's fair to wonder, I think, if he could really have possibly grown and developed enough in one year to somehow reclaim his status as a wunderkind after being so brutalised last season.

Sierra is wiry-strong, undersized a bit at 5'11" and 160 lbs, but there is room on his frame to add probably 15-20 lbs, at least, without compromising his speed and agility. He already possesses well above-average bat speed, and when he connects he's capable of hitting the ball remarkably hard for a player who doesn't necessarily look like a slugger. That being said, for now it's below-average game power, and one has to worry about whether the physical maturity and strength gains to add thump to the bat will actually come about or not.

Defensively, though, there's much less concern. Sierra is the fastest runner and best center fielder in the system, better even than Charlie Tilson, whose glove tends to get plenty of love around the minors. Sierra might legitimately grade as a 70 runner, and a 65 or 70 defender. The floor is still quite low, because there is a chance he simply doesn't hit at all at the upper levels, but elite defense at a premium position can take a player a long way, and Sierra has that in spades. It's a big arm, too; enough to play right field if need be, or just make highlight-reel throws from center all day long.

Player Comp: Kevin Kiermaier is a potential comp as an elite center field defender with enough bat to be very valuable, as are players like Juan Lagares and (gulp), Peter Bourjos. Sierra's offensive upside is, I believe, higher than most of those players, though, with potentially plus contact skills and above-average gap-type power both possibilities. In that case, someone like Lenny Dykstra doesn't feel entirely inappropriate. Only hopefully without, you know, being Lenny Dykstra. Ugh.

via ThePeoriaChiefs (watch 'til the end, as the last couple minutes have some Sierra highlights, including a throw, a catch, and his only home run at Peoria):