Cruz pitched for the Rays last season and struck out 8.5 batters per nine innings while throwing a fastball that averages about 93 MPH. Unfortunately, he walks far too many batters, which is why he's available on a minor-league deal.
Still, Cruz is only a few years removed from some strong seasons with the Diamondbacks, and even in 2010 and 2011, he wasn't horrible. It's odd that he would choose the Pirates, who already have plenty of relief depth. Nearly all bullpens are volatile, and the Pirates' is far from bulletproof, but it's odd that Cruz's agent couldn't find a better situation than this. It's not yet clear whether Cruz's deal contains an out clause, but if it does, the most likely scenario here is that he fails to make the team and then heads elsewhere in late March or in April. He's a nice depth piece to have around, but the Pirates probably won't get to make much use of him unless there's a rash of injuries.