This is fairly surprising news. Mike Patterson's agent, JR Rickert, posted an update on his website saying that Patterson could be back soon.

Mike Patterson has been released from the hospital and will join his teammates at training camp. He is scheduled to see a neurologist in Philadelphia in the next day or so. We anticipate that he will be cleared to resume normal team activities within a few days.

Now, I'm not totally sure what "normal team activities" actually means, but if it's practicing that would certainly be a surprise given his diagnosis. However, it should be noted that his agent was cautioning that the AVM diagnosis was not official and that he was seeking other opinions.

Even if Patterson does return to camp for meetings etc, that would seem to be an indication that he expects to play this year.