Top prospects get Opening Day nods

At this time last year, nine Top 100 prospects had made their first Major League Opening Day rosters. In the ensuing months, three catchers among them best exemplified how reality falls short of, meets or exceeds expectation.

Jesus Montero (Mariners), Devin Mesoraco (Reds) and Wilin Rosario (Rockies) were seen as having varying levels of potential, but only Rosario -- the least-regarded of the three -- was at his best throughout 2012. That's not to say Montero and Mesoraco, talented young players in their own right, were ever at their worst, but extremes are more intriguing than averages, aren't they?

With that, MiLB.com previews this year's elite rookies-to-be.

Jose Fernandez, SP, Miami Marlins

Best Case: Spring injuries to Henderson Alvarez and Nathan Eovaldi have opened up a surprise roster spot for MLB.com's No. 7 prospect, Jose Fernandez. Despite being just 20 years old and having never pitched above Class A Advanced, the precocious Fernandez holds his own with the second-division Marlins. His explosive four-seamer, sinker, curveball combination astounds batters 10 years his senior even while his cockiness -- or is it merely confidence? -- rankles his elders. Fernandez becomes the anchor upon which future Marlins success -- and fan interest -- is built.

Worst Case: Fernandez gets just a handful of April starts, and the Cuban struggles in the cold of Flushing and the Twin Cities. His fastball sits in the middle of the zone and his stuff isn't in midseason form. Fernandez is sent back to Double-A Jacksonville before May 1 where he'll still have nearly three months of pitching until he turns 21.

Shelby Miller, SP, St. Louis Cardinals

Best Case: MLB.com's No. 25 prospect Shelby Miller not only holds down the fifth spot in the Cards' rotation but starts challenging for second-in-command behind ace Adam Wainwright. And command is the reason: Miller spots his mid-90 mph fastball to both sides of the plate, racking up strikeouts and groundouts with the best of them.

Worst Case: The 22-year-old right-hander acts his age, as big leaguers sit on his heater and watch his stagnating off-speed stuff miss the zone. Plus, Miller struggles with the longball -- the 24 he served up in 27 Triple-A starts a year ago prove to be the tip of the iceberg. Before its top pitching prospect can settle down, St. Louis calls on Redbirds options Michael Wacha and John Gast to replace him, potentially living to regret the awkward exit of veteran Kyle Lohse.

Julio Teheran, SP, Atlanta Braves

Best Case: MLB.com's No. 31 prospect Julio Teheran finally puts it all together, flashing his fast arm on the mound and relying on tutoring from Tim Hudson on how-to situational pitching. The 21-year-old right-hander jumps out in front in the Rookie of the Year race before finishing his campaign with 35 starts. The Braves' faith is rewarded.

Worst Case: All those no-hit appearances in Spring Training prove to mean little as Teheran struggles out of the gate. He loses touch on his slider-curve combo and becomes the kind of one-dimensional hurler that some think makes him a reliever long-term. Oh, and Atlanta starts wondering if it should have sent Teheran -- not comparable righty Randall Delgado -- to Arizona in the winter trade for Justin Upton.

Jackie Bradley Jr., OF, Boston Red Sox

Best Case: MLB.com's No. 32 prospect Jackie Bradley -- the one among these 10 who most earned his way onto a roster with his February and March exhibition statistics -- slowly rises to the top of the Red Sox's batting order. The on-base percentage he compiled between two Minor League levels in 2012 (.430) dips just below .400, but he still challenges for the club lead in that category. He's also so impressive in left field that the Red Sox decide by midsummer to not delay the inevitable any longer, replacing Jacoby Ellsbury in center with a building block in the years to come.

Worst Case: Feeling the pressure to keep his Spring Training production at a peak level in the pressure-packed confines of Fenway Park, Bradley falls flat. He swings and misses so often -- and gets on base so rarely -- that his impactful defense in left field is forgotten. The Sox send him to Triple-A Pawtucket just as they might have done at the end of camp, only now he is on the 40-man roster and his arbitration clock has started to tick.

Trevor Rosenthal, RP, St. Louis Cardinals

Best Case: MLB.com's No. 43 prospect Trevor Rosenthal becomes in the bullpen what Miller becomes in the rotation -- an immediate leader. Rosenthal matches his 2012 results (2.78 ERA and 25 strikeouts in 22 2/3 late-summer innings) and, going above and beyond in the absence of injured closer Jason Motte (strained elbow), takes the reins in the ninth inning. The National League Central's best team also has the division's best young closer -- OK, second-best to Mr. Chapman in Cincinnati.

Worst Case: The 22-year-old righty burns out in the bullpen and, with the Cards' rotation still filled to the brim, is sent back to Triple-A Memphis to rebuild his innings count and sharpen his secondary pitchers. Only now that he's been trained physically and mentally to be a reliever, his Wainwright-like transition to a starting role feels a lot like starting from scratch. He falls behind Miller, Wacha and even young Tyrell Jenkins on the prospect totem pole.

Jedd Gyorko, 2B, San Diego Padres

Best Case: MLB.com's No. 50 prospect Jedd Gyorko proves two things by April 30. 1) that his grand slam-beginning to Spring Training was an accurate precursor to his Major League power; 2) that his glove is better suited to second base than skeptical scouts may have realized. He gets his fair share of Rookie of the Year votes.

Worst Case: Gyorko, 24, proves two things by April 30. 1) the injury to third baseman Chase Headley (fractured thumb) has created too much pressure on his bat (he's now hitting in the middle of the order) and his defense (he's shifted to a hot corner and isn't up to snuff there); 2) his 30-homer Minor League season in 2012 is now clearly the direct result of playing in the hitter-friendly Texas and Pacific Coast leagues. Not even the moved-in fences at PETCO Park allow him to reach the 15-dinger mark, but he still contributes and stays in San Diego for the duration.

Wily Peralta, SP, Milwaukee Brewers

Best Case: MLB.com's No. 64 prospect Wily Peralta, like Miller, is more the pitcher who shined in his big league introduction down the stretch than the one who was chewed up and spit out by the PCL. Peralta deftly controls the movement of his sinking fastball and power curve, giving up the occasional home run by circumstance.

Worst Case: The 23-year-old righty walks three or four batters a game -- he issued 78 free passes in 28 outings at Nashville in 2012 -- and he stops pitching to contact, trying to strike out every other batter. His up-and-down success rate is too random for his skipper, and the GM gets the message, calling on Tyler Thornburg as an alternative. And, yeah, that three-year deal with Lohse looks awfully good, as he -- not Peralta -- slots nicely behind Yovani Gallardo on the staff.

Adeiny Hechavarria, SS, Miami Marlins

Best Case: MLB.com's No. 82 prospect Adeiny Hechavarria -- a 23-year-old Cuban export known for his superlative glove work just like the next prospect on this list -- hits a bit better than he did during his 41-game stint in Toronto last year (.254) and finds the gaps frequently. He also expedites his maturation on the basepaths so quickly that he's racked up 15 steals by the All-Star break. Fans -- and fantasy baseball players -- across the nation finally learn how to spell his surname.

Worst Case: Hechavarria proves that his bat will never come close to matching his mitt and he's just one of many so-so ballplayers on a very so-so ballclub playing in a city that won't show up at the stadium it helped pay for. Hechavarria spends the year trying to figure things out in the Majors, but when the season expires in September, he's exactly what he was in April -- a good fielder who can't hit.

Jose Iglesias, SS, Boston Red Sox

Best Case: MLB.com's No. 96 prospect Jose Iglesias has a batting average that hovers in the .275 range and he plays his usual brand of outstanding defense at the infield's most arduous position. Boston's brass gives offseason acquisition Stephen Drew (concussion) all the time he needs to come back -- and they're not sure they need him back at all.

Worst Case: His batting average hovers in the .200 range -- scouts consider changing it from the "Mendoza line" to the "Iglesias line" -- and he plays his usual brand of outstanding defense. Boston's brass demotes him to Triple-A Pawtucket, where he still hits at a Double-A level. His growth stunted, Iglesias is viewed as nothing more than a one-dimensional utility type, a luxury contenders -- not cellar dwellers -- can afford to keep on their benches.

Aaron Hicks, CF, Minnesota Twins

Best Case: MLB.com's No. 98 prospect Aaron Hicks makes the best case in recent memory that Triple-A is for suckers, claiming Minnesota's leadoff spot and excelling while showing off his plus defensive skills in center field. No one worries about starting Hicks' arbitration clock because the Twins' rebuild turns out to be a reload, and fans forget the names Denard Span and Ben Revere. One name that is on the top of their tongues: Torii Hunter.

Worst Case: The 23-year-old switch-hitter makes the best case in recent memory that Spring Training stats are for suckers. The contact rate and power he showed in Florida disappear in American League Central cities like Chicago and Detroit, and he is relegated to Rochester of the International League, spending the bulk of the year there to iron out his swing. Twins ticket holders spend their free time reading Minor League box scores.