Ouch. From the tweet:
Williams is unsigned at this point, a free agent. Given this surgery, my guess is that he'll miss more than the first couple of months of the season. Along about July, he may be able to pitch, but will be without a contract, and out of condition. 2017 would be a more likely time for a return/comeback - if any. In other words, he doesn't pitch at age 34, and attempts a comeback at age 35.