User blog comment:PUNCHURPREGNANT/Gray and Silver Predictions/@comment-24784846-20140507204723/@comment-7418318-20140507221603

While I agree that Silver is extremely unlikely to be future Gray, your argument doesn't disapprove that theory one bit.

What does it matter if he traveled back 40 years or 400 years in time and ended up turned into a Demon upon arrival.

Just a little messup in the timetravel preparations and he could have ended up in Zeref's time. Or maybe he even went there intentionally to do what the original Eclipse Project was supposed to do - kill Zeref before he became immortal - but ended up beaten and changed or taken in by rethorics.