This from E! news, it is well over a year old, but may explain his recent absence from the public stage:
http://www.eonline.com/News/Items/0,1,7748,00.html
Law & Order's Michael Moriarity entering rehab after Vancouver judge orders him to stay away from his live-in girlfriend, whom he assaulted. The charges will be dropped if he complies with the order for one full year.