Dave Meltzer reports that Christian has undergone surgery for a torn pectoral muscle

That's the lead item in Meltzer's Thursday news update:

--Christian underwent surgery for a torn pec and will be out of action for about six months.  That explains the injury angle on Smackdown that airs tomorrow night and the abrupt dropping of the feud between he and Alberto Del Rio.

It should be noted that this is a fairly common injury amongst WWE wrestlers in recent years.  Most memorably, Edge and John Cena both had to vacate their World titles in 2007 after suffering similar injuries to Christian.  Both rushed back to action in less than the recommended six months healing time.  More forgetably, Rory McAllister of the now long since forgotten Highlanders team suffered a torn pec early the next year.

Irv Muchnick is already insinuating that Christian's injury may be due to steroids.