The offense is also a concern. He was never a great hitter and he's been even worse than that overall (better with Atl, but still much worse than his career overall).His bigger concern may be the defense. His offense is creeping back to pre-injury. He was never a good hitter, just an avg hitter with a good glove at SS. In a SSS, his defense is negative now.
I do think there is plenty enough reason for potential suitors to think he can bounce back to the 3-4 fWAR SS he was before the injury. But I also don't see anyone paying a premium to take that risk, even in a market devoid of quality SS options.