This is in the subscriber's area, so I can't excerpt it here, but BA has writeups of 13 players they think have a good chance of being selected, as well as a list of 20 others. The first category includes Brett Lorin and Diego Moreno. They describe Lorin as a command-and-control guy who throws 87-91 and projects as a fourth/fifth starter, which would be why he's not on the roster. With Moreno, I remain convinced there's some issue we don't know about, possibly just doubts about whether he can stay healthy.
Andrew Lambo is listed in the 20 others.
A lot of the players with writeups are RHPs who profile as relievers. The Pirates already have, if anything, an excess in that area. There's one lefty, T.J. McFarland of the Indians, who looks like a Scott Sauerbeck-type LOOGY. That's an area of need for the Pirates.
The position players include Ryan Flaherty, a lefty-hitting infielder who's gotten lost in the Cubs' minor league third base depth. BA says he's not so hot defensively, but he has a solid all-around bat. He's struggled, though, in limited AAA time.