The Patriots also signed rookie tight end Tyson DeVree, who joins Benjamin Watson, David Thomas and Stephen Spach at that position.
Pollard signed with the Patriots on April 23 after being released by Seattle, where he spent one season. He played his first 10 seasons with Indianapolis and two with Detroit.
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"It wasn't really going to work out here the way that we had hoped and he had hoped," coach Bill Belichick said. "At the same time, there are still a couple preseason games left and time before the season opener and I think there are some other teams that are looking for tight ends. Maybe there is a better opportunity for him somewhere else."
In 191 games, including 133 starts, Pollard caught 349 passes for 4,280 yards and 40 touchdowns. Last season, he had 28 catches for 273 yards and two touchdowns in 14 games.
DeVree originally signed with the Patriots on May 5 as a rookie free agent and was released on June 11. He played two seasons at Western Michigan and two at Colorado.