The only info available so far are two things that I've read:
1) When he threw off the mound he said that he still 'didn't feel right'
2) It will be about 4 weeks from the point where he throws off the mound and he DOES feel right before he will be back pitching in the majors
At this point that would mean his soonest return would be right after the ASB and that's only if he goes out today and has a great session on the mound. I've heard of no further mound sessions scheduled at this point though.