Furcal has more upside than your typical injury-prone 34-year-old shortstop who posted a WAR of 0.5 last year, but it's worth keeping in mind that ... well, he's injury-prone, he's 34, and he posted a WAR of 0.5 last year. He did hit pretty well down the stretch, and he was excellent in 2010. It's unclear how much of his poor performance in the early part of the season was due to the various injuries he was dealing with at the time (including a thumb injury that probably made it pretty hard to hit), but he's had so many injuries that his poor performance as a result of one can't just be waved away.
I'd be happy with Furcal as a Pirate next year, but keep in mind that he openly talked about retirement early last season, so he doesn't seem to be the hang-around-forever-even-if-I-have-to-play-for-the-Pirates type, and it's an open question whether he'd be willing to sign. I also wouldn't go longer than two years for him, and even that sounds risky. Maybe he can be lured with a one-year deal with a nice base salary (say, $5 million) and good, reachable incentives as well, giving him a chance to make a nice chunk of change and prove he can stay healthy before heading back to the free agent market next offseason. I doubt it, but it's worth a shot.