This isn't a significant signing, but it's probably noteworthy enough for mid-October, since Balester has pitched parts of five big-league seasons. He was in the Pirates organization in 2014 rehabbing after Tommy John surgery and made some appearances late in the year, so the Bucs may have had some sort of understanding that he would return in 2015, when he figures to be healthy.
In four seasons with the Nationals and one with the Tigers, Balester posted a 5.30 ERA with 7.0 K/9 and 3.8 BB/9. He did better as a reliever than as a starter and had a fastball that averaged 94 MPH as a reliever in 2010 and 2011, so there might be a hint of upside there if those velocities are still relevant now, after the surgery. He'll surely at least pitch at Indianapolis at some point next season, health permitting.