Pirates Prospects is reporting that the team has signed three players from the Dominican: left-handed hitting corner outfielder Eddy Vizcaino and middle infielders Melvin Jimenez and William Calderon. Vizcaino is evidently the most significant of the three, although it's very hard to be sure with international players, especially when bonus information isn't available, as is the case here.
The Pirates were probably hampered this year by having one of the lower bonus pools, thanks to MLB's desire to level the playing field, or something. They do have $269,900 in extra pool money that they acquired for Ike Davis. Even so, the Pirates as a general rule don't bid on top international prospects and instead rely on Rene Gayo's ability to uncover bargains.
There's more information about the players at the link.