Pollard announced his departure Wednesday on Twitter, writing, "Well Ravens Nation. it's been fun. My time in Baltimore is done."
The 28-year-old Pollard signed a three-year extension with Baltimore last season, but his release saves the Ravens an estimated $1 million against the salary cap.
Pollard played two years with Baltimore. Last season, he had 71 tackles and an interception despite playing much of the year with six broken ribs.
Pollard was the leading tackler last season for the Super Bowl champions and was the team's physical presence in the secondary. He forced a key fumble in the AFC Championship Game in New England, when he delivered a vicious hit on New England Patriots running back Stevan Ridley.
Ravens fullback Vonta Leach reacted with surprise to Pollard's news in a tweet of his own Wednesday.
"Wow my boy @Crushboy31 is gone great teammate and father on and off the field," he wrote.
This offseason, the Ravens already have lost seven members from their Super Bowl team.
Baltimore has released Pollard and guard Bobbie Williams, traded wide receiver Anquan Boldin to the 49ers, lost linebackers Dannell Ellerbe and Paul Kruger in free agency and watched linebacker Ray Lewis and center Matt Birk retire.
Information from The Associated Press was used in this report.