The Packers have already confirmed the news and announced the signing of tryout WR Darrius Shepherd.
Sullivan started one game for the Eagles last year and was a core special teams contributor.
Sullivan, 22, wound up signing on with the Eagles in 2018 as an undrafted free agent out of Georgia State. He agreed to a three-year, $1.71 million contract with Philadelphia, but was waived coming out of the preseason.
The Eagles re-signed him to their practice squad after he cleared waivers before eventually promoting him to their active roster.
In 2018, Sullivan appeared in five games for the Eagles and recorded seven tackles and no interceptions.