MLBTR has the scoop on the player to be named later in the trade that sent outfielder Matt Diaz from the Pittsburgh Pirates to the Atlanta Braves:

The Pirates announced that they have acquired right-hander Eliecer Cardenas from the Braves to complete the deal that sent Matt Diaz back to Atlanta last month. The Braves acquired Diaz from Pittsburgh for a player to be named on August 31st, the last day for teams to add players who are eligible for the postseason.

Cardenas, 23, reached Double-A this year, though he spent most of his season at Class A. The Dominican pitched 59 2/3 total innings, all in relief, and posted a 2.11 ERA with 11.5 K/9 and 5.3 BB/9 (his ERA with Class A Lynchburg was 0.79). The Braves selected Cardenas from the Twins in the minor league phase of last winter's Rule 5 draft.

He's kind of like a poor-man's Juan Abreu -- a nice arm we stole from another organization, but nothing the Braves system can't live without. That said, he has possibly the best slider in the Braves system, when he's locating it. At times the pitch is absolutely unhittable, and he was able to dominate Carolina League hitters with it, but he was unable to repeat that success when promoted to double-A late this season, and was sent back to A-ball.

He is purely a relief prospect, and if he can continue to adjust as he moves up the minor league ladder -- especially in double-A -- then he could be a good middle reliever candidate in the Majors. Of course, this is something that the Braves have in spades in their system, so Cardenas was completely expendable from their standpoint. Still, Pittsburgh got a nice, albeit older, bullpen prospect who could learn to dominate with his slider.