Smith, 27, lasted close to two weeks with the Giants before being cut loose. The odds of him making the team were good in the first place given that New York currently has Ryan Nassib and Josh Freeman behind Eli Manning.
Bradford, 25, was a sixth-round pick of the Tampa Bay Buccaneers back in 2011. He spent two years with the Seahawks before he waived and later claimed off of waivers by the Giants. Last year, he appeared in 10 games for New York and totaled four tackles.
Mertile, 24, went undrafted out of a Florida International last year. He was originally a receiver before converting to defensive back not too long ago.