Smith was a seventh-round pick of Tampa Bay out of Utah State in 2012. The speedy 5-foot-9, 205-pound running back had three kickoff returns for the Buccaneers as a rookie, but didn't play in a game last season. He was released in May.
Hardin, a third-rounder by Chicago in 2012, was dealing with plantar fasciitis and missed the last few days of practice with the injury. He was released by the Bears last October and signed to a reserve/future contract by the Jets in January.
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