Morgan was drafted by San Francisco in 2008. He played four seasons with the 49ers, two seasons with Washington and with Chicago last season. He has 209 career receptions for 2,558 yards and 12 touchdowns.
Coley, Johnson and Prater were undrafted rookies.
Coley had eight sacks last season at Virginia. Johnson was a four-year starter at North Texas. Prater led Northwestern in receiving in 2014.
Hocker was a seventh-round draft pick by Washington in 2014, but was cut after preseason.
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