The Pirates announce that they have outrighted Jose Tabata to clear space for Neil Walker on their active roster. Tabata was out of options (since the Pirates used those options in 2009, 2010, and 2012). The outright means that no other team wanted to take on his contract. Tabata has never been outrighted before, but he did have the right to refuse the assignment, because he had more than three years of service time. (UPDATE: I got this detail wrong before. My fault.) Obviously, he wasn't going to become a free agent, given that doing so would have involved giving up the rest of his contract. He's now off the Pirates' 40-man roster, and they have no obligation to add him again at any point. He does, obviously, get the remainder of his contract, which is guaranteed through 2016.
Tabata was not optioned, which is an idea that's floating around Twitter. You only "option" a player who's on the 40-man roster. Outrighting a player, which is what the Pirates announced they did, involves removing him from the 40-man roster.
This is good news, for whatever it's worth. The Pirates are still on the hook for Tabata's contract, which is surely what prevented other teams from claiming him. Meanwhile, they keep a left-handed bat on their bench in Travis Snider who might well have been claimed, since he's not signed long-term (although maybe not, and since he's arbitration-eligible again this fall, he'll probably be gone in a few months anyway). It wouldn't have bothered me if the Pirates had designated Snider for assignment, but having both Snider and Tabata in the organization is better.
The Pirates owe Tabata about $10.25 million through 2016, so it appears no team wanted to gamble on him at that price. He's still listed as being only 25, but he lacks upside -- he's a ground ball hitter who has no power. He also has no speed, having slowed down amazingly quickly since stealing 44 bases between the minors and majors in 2010. He isn't good defensively, either. He's hit .282 and .289 the last two years, which is why the Pirates haven't cut bait before now, but those batting averages are about as empty as they possibly could be.