It seems every year there is at least one prospect who, despite not being regarded by the industry as a whole, blows past expectations in spring training and earns a spot on an Opening Day roster.

Most of the time, they are guys who do one or two things well: They have enough of one tool that their projected floor performance in the major leagues at least should be tolerable.

At the same time, if the player doesn’t meet those expectations, then his team won’t have to worry as much about a demotion or reduced playing time hurting his development as they would with a top-ranked prospect.

Here’s a look at some boom-or-bust prospects worth following closely in spring training.

 

Peter O’Brien, C, Arizona Diamondbacks

Peter O’Brien furthered his reputation as one of the minor league’s premier sluggers last season by launching 34 home runs in 427 plate appearances between the High-A and Double-A levels. But as has been the case during his career, O’Brien’s power came at the expense of consistent contact, as the 24-year-old fanned 26 percent of the time in 2014 compared to a five percent walk rate. That said, he still batted .271/.316/.594 and showed some defensive value by playing first base, right field and catcher.

When the Diamondbacks acquired O’Brien from the Yankees last July at the trade deadline, they did so for his potential to hit 25-plus home runs and possibly stick behind the plate. You see, he has long been scrutinized for his raw defense; detractors point to the natural challenges associated with his 6’3” frame, arguing that it limits his mobility and blocking ability.

However, the Diamondbacks believe O’Brien can handle catching in the major leagues, especially after the work he put in defensively during last year’s Arizona Fall League. In fact, general manager Dave Stewart recently stated that O’Brien could be the team’s long-term catcher, per Nick Piecoro of The Arizona Republic:

After trading Miguel Montero during the offseason, Arizona is, for whatever reason, content with opening the season with a combination of Tuffy Gosewisch, Gerald Laird and Rule 5 pick Oscar Hernandez behind the plate. It also means O’Brien could receive an extended look this spring, as he’s already drawing rave reviews for his exploits in batting practice.

While O’Brien’s power and upside certainly stands out most in the group—even if it translates to a high strikeout rate and low batting average—it will be his glove that ultimately determines his role and impact in the major leagues.

 

Steven Moya, OF, Detroit Tigers

Speaking of prodigious power, Steven Moya’s has always ranked among the best in the minor leagues, but a rash of injuries—including Tommy John surgery—caused him to fall behind the developmental curve, which is why he reached Double-A Erie for the first time this year in his sixth professional campaign.

Suffice it to say that Moya helped to make up for the lost time in a big way, as he was named MVP of the Double-A Eastern League after leading the circuit in home runs (35), RBI (105), extra-base hits (71) and slugging percentage (.555)—all career highs. He also set a single-season franchise record for Erie with 286 total bases in addition his batting totals. The Tigers rewarded Moya for his breakout season with a September call-up,

A 6’6” left-handed hitter, Moya’s bat speed, strength and leveraged swing fuel his enormous raw power to all fields, but there continues to be concern about his capacity to hit big league pitching. The 23-year-old’s path through the zone can be long, and he still lacks any semblance of plate discipline, which explains his 29.3 percent strikeout rate and 4.2 percent walk rate last season in 549 Triple-A plate appearances. Meanwhile, Moya continues to do the majority of his damage against right-handed pitching.

Even though manager Brad Ausmus has stated that Moya is unlikely to break camp with the team, there’s still a chance the Tigers will consider him for a bench role to begin the 2015 season if either Miguel Cabrera or Victor Martinez haven’t recovered from their respective injuries. If that were to be the case, then most of Moya’s at-bats would likely come as the designated hitter.

 

Frank Montas, RHP, Chicago White Sox

A pair of knee injuries limited Frank Montas to only 15 starts in 2014, his first season with the White Sox, but the right-hander still made a strong impression during his time with High-A Winston-Salem and Double-A Birmingham and then opened even more eyes in the Arizona Fall League.

The 6’2”, 185-pound right-hander boasts a fastball in the high 90s that eats up opposing hitters. However, in spite of his improved control last season, Montas‘ delivery involves considerable effort and currently impedes his ability to locate pitches within the strike zone; he won’t dominate as many hitters at the top of the zone at higher minor league levels. Montas struggles to throw strikes consistently with his above-average-to-plus slider and average changeup, with the former serving as his best swing-and-miss offering.

The 21-year-old may be best suited for a bullpen role at the highest level, but any additional improvement to his secondary arsenal and command profile should further his stock as a potential starter.

Montas is a candidate to receive more innings this spring in the wake of Chris Sale’s foot injury, according to Scott Merkin of MLB.com. He’ll have to really impress the organization to win a spot, however, as he’ll be competing against fellow prospects Carlos Rodon and Chris Beck.

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