Angel Pagan (49%)
Pagan's 2013 season was shortened by injury and he's looking to bounce back in 2014. The one thing to keep an eye on is how much of his speed he maintains as he enters his age 32 season. While he has okay batting average/obp and pops the occasional homer, the bulk of his value depends on him being in the 30-35 steal range that he was in from 2010-2012.
His most similar player through age 31 is Roy Weatherly. It's about guaranteed that Pagan has better results going forward than Weatherly (who's nickname was Stormy). Weatherly only had 82 more plate appearances which came a few years later when he was 35.
Nick Castellanos (44%)
Castellanos got his first taste of major league action in 2013, getting 18 plate appearances towards the end of the season. With Castellanos, keep an eye on how he does in spring training and ultimately what role he's in to start the year. He's done good so far this spring (.905 OPS in 25 plate appearances) and he's been a top 50 prospect for the last couple of seasons.
Looking at his minor league numbers, he had respectable numbers in AAA last year (.793 OPS) but nothing that suggests that he would be very strong against major league pitching this year. For the long term keeper leagues, there's upside since he's only 21 but I think he starts getting regular playing time this year he'd probably struggle for a year or two first.
George Springer (30%)
Houston Astros fans don't have too much to be excited about these days but George Springer shows some glimpse of hope for the future. If he puts up numbers that even somewhat resemble what he did to minor league pitching last year (.303/.411/.600 37 homers, 45 steals) he's going to be an absolute monster. Also, I think any growing pains in the bigs will be somewhat absorbed by the fact that he has a patient eye at the plate (83 walks last season).
He could ultimately be an Adam Dunn three true outcomes type of player with a whole bunch of stolen bases thrown in. Last year he had a home run (37), walk (83) or strikeout (161) in 47.7% of his plate appearances. He is off to a rough start in spring training which will likely be used to keep him in the minors for a couple months to avoid him becoming a super 2 but this is a player that has the potential to swing the outcomes of fantasy leagues once he gets called up.
Avisail Garcia (25%)
Garcia ended up going from the Tigers to the White Sox as part of the three way trade that sent Jake Peavy to the Red Sox. For both 2012 & 2013 he was in the top 10 for youngest player in the AL.
He did play reasonably well after going to Chicago .304/.327/.447 106 OPS+ 5 homers/3 steals. Since the White Sox aren't expected to contend, I think Garcia gets his share of plate appearances. The question standing is if he'll do enough with those appearances to produce any value.
He's accomplished all that he can in the minors last year (.991 OPS) in 47 games. Most of the value came on the batting average side as he hit for a good average but hasn't hit more than 14 homers in a given season. Another concern in the minor league numbers is that he seems to be a free swinger as he never drew more than 20 walks in a given season. I think his power will develop as he gets older (he's only 22). It's whether he can get more selective and draw some walks that will determine whether he will have consistent value as he gets older or he's on the path to being a 4A player. For 2014, i'll pass.
Rajai Davis (25%)
Basically, Davis is a one-trick pony (stolen bases) when it comes to fantasy. It happens to be a trick that he's very good at (40+ steals four of the last five seasons). At age 33, it's legitimate to ask how much longer it will be before the speed fades away as he gets older. He may be okay on the batting average side if things break right but there's little to no value on the power side.
Through age 32, his most similar player is Scott Podsednik. At age 33, he hit for a decent average/obp (.304/.353) but he still had 30 stolen bases left in him (plus 35 the next year) before his career came to an end (with the exception of a few appearances with the 2012 Red Sox). For Davis, I think there is some value if you are in need for stolen bases though I would like for other options first. I think Davis has one or two season of decent value based on stolen base totals.