Smith played for the Giants from 2007 to 2010, totaling 220 receptions for 2,386 yards and 11 touchdowns. Smith made the Pro Bowl in 2009, when he posted a franchise-record 107 receptions for 1,220 yards and seven touchdowns.
He signed with the Eagles in August after he met with the Giants and coach Tom Coughlin said Smith still had "a ways to go" before being healthy enough to play again.
Quinn was the 14th overall pick, while Watkins was the 23rd pick but had lost his starting job to recently signed Kyle DeVan.
Rams wide receiver Danario Alexander also is inactive.
Information from The Associated Press contributed to this report.