Gaston has appeared in two games this season with the Green Bay Packers, with one tackle.
In the preseason, Gaston had three tackles - including a sack - and four quarterback hits. Gaston entered the league in 2014 as an undrafted free agent with the Arizona Cardinals out of Purdue.
Ferguson has appeared in 20 games with one start over two seasons (2014-15) with Chicago, with 36 tackles and two sacks.
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