Or, using polite parlance, "released". Same difference. Per a very busy (and we appreciate it!) Gary Fitzgerald at the Official Site:

Big shocker as everyone could see the writing on the wall. We had him gone in December due to a hefty 3M cap hit in 2007 despite being (essentially) the 5th WR on the roster behind Moss, Randle-El, Lloyd, and James Thrash. The move saves the team some change and I think we all knew it was just a matter of time. I felt the only reason the team might be waiting was to cut him June 2nd and spread the cap hit into '08, but by all indications (given the handling of the Archuleta deal, among other things) the team is prepared to take its licks in '07 and move on beyond that.

I will update the post with the actual numbers once we know how much this saves. Best wishes to Patten, but he simply wasn't productive or moving up the depth charts enough to justify his paycheck.