This article is a little dated, but Mike Berardino wrote a nice piece about Jeremy Hermida. If you weren't excited about Hermida already (though he's still in Double-A), this comparison to Larry Walker might encourage you to be:
Now that a trade of Burnett and Lowell seems less likely (the Herald is reporting that Burnett could go to the White Sox - sans Lowell - for Damaso Marte and Brandon McCarthy), we may not see Hermida as quickly. But my guess is still that we see him at least by Opening Day in April.
(As an aside, if that trade goes through with the White Sox, I much prefer the trade for the Marlins in the long run. McCarthy is a top level prospect and Marte is a force out of the pen. Still, I'm not sure that the trade materially improves either team for this season.)