http://www.mysanantonio.com/sports/spurs/Ginobili_hampered_by_sore_right_ankle.html

"The ankle had been bothering Ginobili for a few days heading into the All-Star break.

(...)

“He just had some soreness,” Spurs coach Gregg Popovich said. “We just wanted to make sure, so we're getting him checked out.”

Popovich admitted it was disconcerting that Ginobili's ankle was still tender after five days of rest.

If it responds to treatment, there is a chance Ginobili could re-join the team on the rest of the rodeo trip (...) That, however, sounded unlikely Tuesday night."

A lingering injury, it seems. But from this article I still get the impression that he would be playing, if the Spurs really needed him.

I guess this also clears any doubt about the possibility of Manu staying behind because he's going to be traded.