The Pirates have signed a bunch of them. Only one, Shairon Martis, appears to be more than minor league filler. Here's a run-down.
Nick Evans a 25-year-old first baseman, BR/TR, 256/305/407. His major league statistics suggest an AAAA player. A decent power hitter with adequate defensive ability and limited speed who could be a useful bench player or AAA depth.
Jake Fox, a 29-year-old catcher and first baseman, BR/TR, has a 301/370/584 slash line in four AAA seasons. He has never played in the majors, and probably never will. But if we get enough injuries, he might.
Brandon Boggs, a 28-year-old outfielder, BB/TR, has a 271/389/432 slash line in four AAA seasons. He has never played in the majors, and probably never will. He has some speed.
Stefan Welch, 23-year-old first baseman, BL/TR, has been stuck in the Florida State League for four years with a slash line of 266/344/415. The purpose of this signing is not clear.
Shairon Martis, a 24-year-old RHP, rather exploded in AA this year. In 133 innings he logged 8.3 hits per game, 0.6 home runs per game, 2.6 walks per game, and 9.9 strikeouts per game. He pitched for the Nationals in 2008 and 2009, but walked a lot of people. He might actually be a player.
Kyle Cofield, a 24-year-old RHP, has been bouncing around AA and AAA since 2009. As a minor league reliever for the White Sox he logged 8.3 hits per game, 0.0 home runs per game, 3.9 walks per game, and 7.5 strikeouts per game. Tough to get excited about.
Jose Diaz, a 27-year-old RHP, is gigantic. To quote WTM, "Some articles on him say he throws in the upper 90s and has hit 100. And he weighs a lot more than 300."
Jeremy Hefner, a 25-year-old RHP, had a good year in AA in 2010 and a bad year in AAA in 2011. He walks too many and strikes out too few to be of much interest.