According to Baseball America, the Pirates have made the following minor-league signings:
IF Brandon Chaves
OF Michael Ryan
3B Tripper Johnson
RHP Kip Bouknight
RHP Allan Simpson
Brandon Chaves is a Pirates organizational infielder who played at Altoona last year and will quite possibly head back there next year.
Michael Ryan is a former Twins prospect who the Bucs were probably interested in for two reasons: he helps with their lack of minor league outfielders, and he's from Indiana, PA (he went to Indiana Area High School). In any case, he was terrible for the Braves' Class AAA affiliate last year and he's almost 30, so he's not going to help.
Tripper Johnson will only be 25 next year and he was once considered a prospect for the Orioles, but he has yet to figure out how to hit Class AA pitching.
Allan Simpson has control problems and a career 5.88 major league ERA, but he's received few big league opportunities and has been dominant at times in the minors - he's struck out about ten batters per nine innings in his minor league career. He apparently has a very good fastball. Of all these guys, he's the one most likely to help.
Kip Bouknight is a run-of-the-mill minor league starter. He'll be in the rotation at Indianapolis or Altoona, depending on who else the Pirates sign and whether Sean Burnett, Jon VanBenschoten and Bryan Bullington can get or stay healthy.