According to an ESPN.com article:
Coach Dennis Allen would give no more information about why he held McClain out. Allen said he did not know if McClain would practice Thursday.
Also, in an article by Paul Gutierrez of CSN Bay Area:
McClain being listed as not participating in Wednesday's practice, despite being on the field at the start during the open media window, and the reason given -- coach Dennis Allen said it was for "team-related issues" -- only deepens the mystery that is McClain.
That said, let's move forward and see which teams could use McClain's skill set to improve defensively.