Via their official site, the Pirates have outrighted Deolis Guerra and, apparently, Travises Snider and Ishikawa. Snider and Ishikawa have elected free agency. Guerra has officially been sent to Indianapolis, although he should now be eligible for minor-league free agency, so it wouldn't be a surprise if he ended up going elsewhere.
None of these moves are particularly surprising. The Pirates treated Snider and Ishikawa as depth pieces down the stretch. They were both arbitration eligible and would have made more than the big-league minimum next year, so they were pretty likely to be outrighted or non-tendered at some point.