the article says that Zimm was getting a drug that is like a steroid. But with "sly" retracting his claims I don't see how this becomes any more than a he-said / he-said unless MLB decides to push the issue.
This looks to have even less factual evidence than the Biogenesis report. At least with that there was a written (terribly) ledger with Biogenesis. While I doubt Zim is totally innocent, I doubt there is anything nearly close enough to incriminate.