Arrington, 28, spent the last five seasons in New England, playing in two Super Bowls. An undrafted free agent out of Hofstra who didn't stick with two other teams, he moved up from the Patriots' practice squad in 2009 and started 56 games for them.
Davis, 29, a six-year veteran with the Redskins, was suspended for the 2014 season for violations of the league's substance-abuse policy. He has 162 receptions for 2,043 yards with 13 touchdowns.
Hughes, 26, has suited up in three games over three seasons, all with the Rams in 2011.
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