The one-time England international will arrive in Newcastle on Friday before training with the club with the view to a two-and-a-half month stay.
Jets executive chairman confirmed Jeffers would be in town tomorrow ahead of a few days of training with the squad.
"He will spend three or four days here training to enable us to assess him appropriately," Edwards told the Newcastle Herald.
"We need to make sure he fits in with the way we operate. If it all works out then we will offer him a 10-game guest stint."