From the official site:
Corey Patterson filed for free agency Wednesday, joining a celebrated class of center fielders that also includes Atlanta's Andruw Jones and Minnesota's Torii Hunter. Patterson is the second Oriole to file for free agency since the World Series ended (z note: the first was Base Knock Bako), but all teams will retain exclusive negotiating rights with their free agents until Nov. 2... Patterson batted .313 with a .333 on-base percentage after the All-Star break in 2007, but a sprained left ankle caused him to miss virtually all of the season's final month.