BA's Ben Badler has a piece on Cuban defectors who have signed contracts with big league clubs since the beginning of 2010.  I'm not a BA subscriber, so I can't see any specifics, but Badler mentioned the Bucs in a tweet regarding the article:

Not sure if it's been reported elsewhere yet, but the Cuban story also has scouting info on a P the Pirates signed for $600K

UPDATE:  Tim Williams at Pirates Prospects has us covered:

The Pittsburgh Pirates agreed to terms with Cuban right handed pitcher Cesar Lopez for $600,000 in September. The deal is still pending the result of Lopez getting his visa.

Badler mentions that Lopez is 20 years old, and is a sinker/slider pitcher who can run his fastball up in the low 90s.