Castillo good, not great, prospect

— -- Cuba has produced its fair share of major league stars in recent years, with players such as Yasiel Puig, Jose Abreu and Aroldis Chapman all having fantastic seasons and looking like fantasy mainstays for the next several seasons.

Those players' success has every club looking for the next Cuban star, and many believe that could be Rusney Castillo, who reportedly came to terms Friday on a massive seven-year, $72.5 million contract with the Boston Red Sox.

Here's a breakdown of why Castillo, 27, has a chance to be a quality fantasy player in the coming years, and also why it's unlikely that he reaches the level of the players mentioned above.

What he can do: Castillo's best asset is his speed, and while it's not elite, it's good enough to cause havoc on the bases, as seen in his 68 stolen bases from 2011 to 2013.

What surprised many scouts who saw Castillo in Miami last month, however, was that his power is not far behind his speed anymore. The right-handed hitting outfielder showed plus pop at the workout, putting on "good" weight since coming over from Cuba, and he has the bat speed and natural loft to his swing to hit tape-measure shots to the pull side while putting the ball into the gaps to the opposite field.

"He could easily be a 20 [homer] 20 [stolen base] guy," a National League scout who saw him work out twice said. "And if everything goes right, maybe he can be a 30-30 player. Guys like this always have a tendency to turn the workout into their own personal home run derby, and everyone saw a lot of that approach. But you also saw a guy with good bat speed, solid athleticism and impressive hand-eye coordination as well. If the approach improves, he could easily be hitting in the middle of the Boston lineup, though I'm sure they'd like that plus-plus speed near the top."

Reason for concern: No scout or front office member I spoke with had concerns about Castillo's athleticism or pure baseball skills, but quite a few had concerns about his mechanics at the plate. His swing is long, and the back half doesn't always work in sync with the rest of his body; with more than one talent evaluator saying that Castillo "collapses" too often. That generally leads to poor timing, and also could lead to some swings-and-misses as he faces far superior pitching at this level.

The biggest concern for Castillo, however, is something that he has no control over: Expectations. Because guys like Puig and Abreu -- and to a lesser extent, new teammate Yoenis Cespedes -- have come over from Cuba and become bona fide fantasy stars in their first few seasons, many in your dynasty league will be expecting similar things for Castillo, based on his contract. Most whom I have spoken to don't believe that's a realistic ceiling.

"I think he's an average regular," an American League West scout said. "And you can do a lot worse than having an average regular on your roster, you need guys like this to win games. If you're expecting him to come in and be Yasiel Puig or Jose Abreu, you're going to come away disappointed -- he just doesn't have the overall skill set to be that good offensively. He's improved enough for me to think he's no longer a fourth outfielder, but expecting him to be a star of that caliber is a fool's errand."

2015 and beyond: The Red Sox aren't going to give $72.5 million to someone they believe is going to be a fourth outfielder, and as a player who will be 28 in June, you should expect Boston to be assertive in Castillo's development. There are certainly openings in the outfield for him to become a regular, though where he'll play is another question mark. With Cespedes in one corner and talented outfielders Jackie Bradley Jr. and Mookie Betts -- plus a difficult-to-trade contract in Shane Victorino -- the Red Sox don't have to rush his bat to the majors right away. I would expect Castillo to come up sometime next summer, and to be a quality fantasy option for those who can sacrifice on-base percentage for steals and some doubles and home runs. Fantasy owners should be hesitant to select him in re-draft leagues, but dynasty players should look into how they can procure his services now, as he should be an above-average fantasy option in the coming seasons.