1. Devin Mesoraco, C, Cincinnati Reds
Mesoraco is a power-hitting catcher who just so happens to have a decent enough glove to stay behind the plate for a while. Because of that, he's arguably a more valuable keeper piece than the Seattle Mariners' Jesus Montero. Mesoraco, a 2007 first-round pick out of a Pennsylvania high school, blossomed as a hitter the last two seasons in the minors by posting a .964 OPS in 2010 and an .855 OPS in Triple-A last year.
Harper no lock to make roster
The 23-year-old shows all the signs to develop into a complete hitter who can hit for average and get on base at an above-average clip. The Reds showed a lot of confidence in Mesoraco when they dealt fellow stud catching prospect Yasmani Grandal to San Diego in the winter. To begin the season, the Reds will use Mesoraco in a catching platoon with veteran Ryan Hanigan, but the organization expects the former to seize the bulk of the playing time eventually.
Mesoraco has the pop to hit 15 home runs or more as a rookie, and he's a talent that could push for All-Star status in the not so distant future.
2. Bryce Harper, OF, Washington Nationals
In keeper league formats, Harper would be the slam dunk No. 1 prospect, and he's hands down the best prospect in all of baseball.
While Nationals manager Davey Johnson has been adamant about being open-minded about Harper's bid for a major league roster spot coming out of spring training, the odds favor the business side of the equation to prevail in this conflict. If he begins the regular season in the majors, they are only guaranteed to have his rights through the 2017 season. If they wait until the summer, they can control his rights until 2018.
Nineteen-year-olds tend to struggle in the majors no matter how gifted they are; Alex Rodriguez (.672 OPS), Justin Upton (.647), Andruw Jones (.709) and Mike Trout (.679) are some telling examples. Despite that fact, Harper is the rare talent who has defied odds several times in his development curve and it wouldn't surprise if he puts up comparable numbers to what 19-year-old Ken Griffey Jr. did (.748 OPS) in 1989. Talent observers are particularly impressed with how fast the 19-year-old makes adjustments to his competition, and that bodes well for Harper when he finally gets his shot.
For fantasy leaguers who care only about 2012, there's real uncertainty about how much Harper will play in the majors this year, but he's still worth the gamble. He should carry strong value even in one-year formats.
3. Yonder Alonso, 1B, San Diego Padres
Buried behind Joey Votto with no clear place to play in Cincinnati, Alonso was traded to San Diego in the offseason as one of the key chips used to acquire starting pitcher Mat Latos. Given that he plays a premium hitting position, Alonso is probably going to draw lukewarm interest in MLB-universe formats because he is slated to play his home games at PETCO Park.
Ballpark aside, the 25-year-old might be in the best playing situation of any rookie this year. He's going to get a chance to log 500-plus at-bats. Even though Alonso's .860 OPS at Triple-A Louisville in 2011 doesn't scream superstar, there's a lot of hidden value in his numbers. He has put up stable batting averages his entire career, he has a strong grasp of the strike zone, and he shows the pop to develop into a 20-homer, 40-double thumper in the heart of a batting order. Alonso also has an all-fields approach at the plate, something that should suit him well at PETCO, which is hell on left-handed batters.
At age 25, Alonso is at the right age to blossom into an above-average hitter, and he has the skill set and track record that support a breakout. He's a sleeper, so don't let ballpark biases override one's perception of him.
4. Drew Pomeranz, SP, Colorado Rockies
Like Alonso's, Pomeranz's new home team is not endearing him to many fantasy players at first glance. Pomeranz, the fifth overall pick of the Cleveland Indians in 2010, was traded to the Rockies at the deadline last year.
Despite going to a team in an unfriendly pitcher's environment, Pomeranz held his own in the majors late last year, pitching well in three of his four starts despite having decreased velocity caused by fatigue. The former Ole Miss star draws rave reviews for his poise and three-pitch mix, but his command can waver at times.
In 2011, Pomeranz struck out an eye-popping 119 batters, allowed only three homers and registered a 1.78 ERA in 101 combined innings in the minors. Because the Rockies lack surefire arms in their rotation, Pomeranz has a chance to stick coming out of spring training, although there's a number to beat out.
Even if Pomeranz starts in Triple-A, he might be the organization's most talented pitcher, so expect him to compile his share of major league starts this year. The left-hander profiles as a No. 2 starter, possibly an ace.
5. Julio Teheran, SP, Atlanta Braves
Teheran is a superior long-term prospect to Pomeranz, but he rates lower on the list because of his playing situation coming out of spring training. With Tim Hudson (back) likely to start the season on the DL, fellow highly regarded pitching prospect Randall Delgado has the edge to start the season as the Braves' fifth starter, with Teheran likely headed to Triple-A Gwinnett to begin the season.
The Columbian Teheran was the youngest player on an International League roster on opening day of 2011, but he didn't play like a kid, recording a 15-3 record, a 2.55 ERA and 122 strikeouts in 144 2/3 innings. He surrendered only five home runs.
Teheran shows admirable command of his fastball, and his changeup is deadly. He has the makings of ace, but a little seasoning couldn't hurt him after he put up a 5.03 ERA and posted a 10/8 strikeout-to-walk ratio in 19 2/3 innings in the majors last year.
There's no doubt Teheran is a budding gem, but he might be a year away from being the fantasy impact pitcher of 160-plus innings one can count on.