Travis Sawchik reports that the Pirates are among the "finalists" for Josh Johnson, and that he's considering "three or four" teams. We heard earlier today that Johnson's preference was to play for the Giants or Padres. Sawchik reports that Johnson wants a one-year deal so that he can increase his value and hit the free agent market again. That Johnson wants to do this probably bodes well for his health, or at least his own perception of his health.
Anyway, if he's healthy, there's little reason to think Johnson can't be a good starter. You can safely dismiss the 6.20 ERA last season. Pointing out that he had an xFIP of 3.58 last season is so obvious that it's almost banal, and there probably isn't a team in baseball that weights the ERA more heavily than the xFIP, so I'm not sure there's a ton of value to be had there, at least on the free agent market. (6.20 ERA seasons are still hard to watch, though, so my guess is that there's still value in trading for pitchers with ugly peripherals and good ERAs once their teams tire of them -- that's how the Pirates wound up with A.J. Burnett and Mark Melancon.) The issue with Johnson is his health, and with forearm and elbow problems last year, how he looks in a physical may turn out to be important.