According to Harbaugh he's suspended indefinitely for undisclosed reasons.By "suspended" he's just going to be red shirted. Something that was likely anyway or at least not a lot of playing time was likely if he wasn't. Whether or not he can get his act together in the mean time before next fall remains to be seen. We got Eddie McDoom as our freshman WR who can potentially actually contribute on the field this year. What a name.
Red-shirting him after being suspended indefinitely only means the infractions serious but the kid is talented enough that Harbaugh doesn't want him to lose a year ( or a major part of one) of eligibility .
Spin it anyway you like, but Ahmir being red-shirted has more to do with the reason he was suspended than anything else.