Bell had been with the Bears since the 2009 season, when he broke a 72-yard run on his first regular-season NFL carry. The former UCLA RB averaged 4.7 yards per carry with 557 yards on 119 attempts in 19 games and three starts. He also had 20 catches for 137 yards.
Monday may have had something to do with Bell's release. He was an unrestricted free agent who signed a $1.26 million tender. Starter Matt Forte has received a new deal with $17.1 million in guaranteed money and backup Michael Bush got a $14 million, four-year deal. Paying another $1.26 million for a third back, when Allen and Booker combined wouldn't make that much, seemed wasteful.
Bell didn't help his cause with three lost fumbles in the final two games last year, and then he fumbled once early in camp.
Booker helped his cause immensely with a 105-yard kickoff return for a TD last week. Allen's receiving ability makes him an attactive option as a third back, but he has yet to show that off in games. He has one catch for no yards in preseason.
Follow Bears reporter Gene Chamberlain on Twitter @CBSSportsNFLCHI.