Joe Ross, RHP, Padres (Low-A Ft. Wayne)

The former first-round pick dealt with injuries and inconsistency last year in what was a disappointing introduction to full-season ball and the Midwest League. This April, Ross returned to Ft. Wayne and has been nothing short of impressive in his first two starts for the Tincaps, tallying 12 strikeouts and just two walks and two hits over 10 innings. In his Opening Day start against the Great Lakes Loons (Dodgers), Ross showed off low- to mid-90s velocity (peaking at 96 mph) with arm-side life and improved fastball command, working the lower-U (both sides and the knees) and taking advantage of a little extra room the umpire was giving to the glove side.

Ross established himself inside early and often to both lefties and righties, working mostly fastballs the first time through the order and adding a low- to mid-80s slider the second time through. He broke out just a few change-ups—most notably three in one six-pitch strikeout of Dodgers 2012 first rounder Corey Seager in their second meeting (the first resulted in a soft 1-3). Ross still tends to open up his front side prematurely, periodically driving his fastballs high and to the right relative to the target, but overall he’s keeping the ball down, missing bats, and inducing soft contact (the Loons hit just two balls in the air and squared up three through Ross's five innings of work). In limited action thus far there is certainly evidence of growth in stuff and improvement in execution. —Nick J. Faleris

Yasiel Puig, OF, Dodgers (Double-A Chattanooga)

Many people, including myself, hadn’t seen Puig before spring training and relied on second-hand reports of his brief 2012 season, which for the most part were very positive. (We ranked him the no. 1 prospect in the Dodgers’ system.) Then all hell broke loose. Puig started spring training at a torrid pace and kept it up until I ventured out to Arizona for a weekend late in March. He finished with a .517/.500/.828 line in 58 at-bats. Our own Jason Cole clocked Puig at 4.04 on a sprint to first base, which hints at his incredible athletic ability. A man that size running that fast is scary. Sometimes it can even lead to problems: I saw Puig take a bad route in center field and try to dive for a ball, knocking the wind out of himself, and the next day he did the same belly-flopping into third base.

The question is whether Puig has the ability to hit major-league quality secondary offerings, and spring training isn’t much of a test in that regard. Double-A Chattanooga could be his toughest test yet, and so far he is crushing there too, batting .414/.469/.759 in 29 at-bats. Puig is a football player playing right field, and he has the baseball skills to make an impact in the majors in the very near future. I’m smitten. —Chris Rodriguez

Mike Olt, 3B, Texas Rangers (Triple-A Round Rock)

Olt’s early-season results haven’t been pretty, as he’s just 3-for-41 (.073) with five walks and 21 strikeouts through 11 Triple-A games. The slugging third baseman has gained a reputation as a slow starter over the past three years, though he didn’t exactly crush the ball after earning the call from Double-A Frisco last August, either. One scout who recently saw Olt in Round Rock remarked that the prospect’s swing has lengthened and he’s having trouble repeating his hitting mechanics. It’s too soon to panic over Olt’s slow start, but he has fallen into some bad habits and doesn’t look like himself at the plate or in the field. —Jason Cole

Will Swanner, C, Rockies (High-A Modesto)

After a breakout full-season debut in 2012 that saw the young catcher hit over .300 and slug 41 extra-base hits in only 88 games, Swanner’s stock was on the rise in the prospect world. From a scouting perspective, Swanner isn’t the hitter his Sally League batting average might have suggested, as the 21-year-old has a leveraged swing that isn’t quick into the zone or short to the ball, and that produces a lot of swing-and-miss. He’s a big puncher who can do serious damage when he lands one to the face, but pitchers with a plan can beat him—both in and out of the zone—which limits the damage he can do with his power. In a hitter-friendly league, Swanner is going to run into his share of bombs, but unless he makes the necessary adjustments, both to his swing and his approach, the strikeout totals could get X-Rated. —Jason Parks

Aaron Sanchez, RHP, Blue Jays (High-A Dunedin)

Sanchez belongs in any discussion of the most live arms in the minors. I got my first glimpse of him in 2010 when he was pitching in the GCL, and after seeing him early this spring, I was impressed with the progress he’s made. His fastball has never been a question. He throws it with ease in the 94-98 range, and the ball just explodes, especially down in the zone. His long stride to the plate gives hitters even less time to react and put a good swing on the ball.

Sanchez throws a tight-spinning 12-6 curveball that has shown steady improvement and is now a second above-average offering that will generate plenty of swings and misses. He still needs to work on developing his change-up, but it has come a long way since his 2010 debut. The major concern with him right now is his command: in his first three seasons, he’s averaged nearly five walks per nine innings. Sanchez has made two starts in 2013, going five innings in each and walking a total of three batters while striking out seven. Control issues aside, Sanchez has the arm action and three-pitch repertoire to advance quickly through the minors, should the Blue Jays decide to push him. —Chris King

Matt Wisler, RHP, San Diego Padres (High-A Lake Elsinore)

One of baseball’s top breakout arms over the last two seasons, Wisler continues to see his stuff and projection tick up. Baseball Prospectus ranked the on-the-rise righty as San Diego’s no. 8 prospect over the winter. It’s safe to say he’d be considerably higher today, as he worked between 92-94 mph during starts in spring training and reached up to 98 late in camp. What was a 3/4 starter projection is now a 2/3 at minimum.

Although Wisler has some funk in his delivery, he repeats well and shows four average-or-better pitches for strikes. He’s off to a fast start at High-A Lake Elsinore, missing bats and tossing five innings of three-hit shutout ball in each of his first two outings. He’ll play the entire season at age 20 and is a definite candidate for a mid-season Double-A look. —Jason Cole

Orlando Arcia, SS, Brewers (Low-A Wisconsin)

Younger brother of (now) major-league outfielder Oswaldo Arcia, the 18-year-old shortstop is ready to jump into the prospect mainstream. After a good showing in the Dominican Summer League in 2011, Arcia was primed for a stateside debut the following season, but a broken ankle took him off the field and put his development on hold for the entire year. Finally healthy, the toolsy Dominican made the jump all the way to full-season ball, where a quick bat and good leather should help create buzz about his potential.

I put eyes on Arcia this spring, and he shows a lot of natural baseball skills on the field. He attacks the ball at the plate, putting the barrel on the ball out front and showing some legit pop for his size. The glove is good, with clean, easy actions and a quick first step for range. He has all the tools, but he’s still raw, so I don’t expect a lot of production at the plate right out of the gate. Give this kid the time to develop and refine his tools, and he’s going to be a player. You can just see it. —Jason Parks

Kyle Zimmer, RHP, Royals (High-A Wilmington)

Zimmer has a calm approach to pitching, with picture-perfect mechanics; in fact, the mechanics may be so clean that hitters are able to pick up the ball early. The curveball has a chance to be a monster, with tight spin and hard vertical break, and the fastball is an established plus-plus pitch, with impressive velocity. Zimmer has a ceiling of a no. 2 starter, but the mature stuff and repeatable delivery also give him a high floor. He is polished to the point that it would not be surprising if he is able to reach the big leagues at some point in 2013. —Zach Mortimer

Adalberto Mondesi, SS, Royals (Low-A Lexington)

I wake up every morning with an intense desire to hype Adalberto Mondesi, and his slow start to the 2013 season hasn’t suppressed those aspirations. In a limited 10-game sample, Adalberto, son of Raul, isn’t tearing the cover off of the ball, and he’s grown quite familiar with the strikeout, with 13 in 40 at-bats.

But context is important here, as Mondesi is only 17 years old and playing at the full-season level, a rare accomplishment, even for the most gifted of players. The fact that he has managed nine hits and three walks in that 10-game sample shows just how advanced he really is, and as the season progresses, he will gain his footing and put together better stretches. This isn’t a season for stats, it’s a season for development, and the more time this kid logs on the field against more advanced competition, the better he will play. —Jason Parks

Jorge Bonifacio, RF, Royals (High-A Wilmington):

Jorge Bonifacio doesn’t play much like his slap-hitting brother Emilio. Jorge has natural ability at the plate and uses his strength to exploit mistakes. He has a short swing, a quick trigger, and power to all fields. In the field, he takes good routes to balls and has average range in right field. He also has an absolute cannon and is not afraid to unleash it at any time. Only 19, Bonifacio shows advanced baseball instincts. The Royals will allow him to hone his craft in High-A for the majority of the season. —Zach Mortimer