Newcastle boss Steve Bruce hopes to sign Joe Willock on a six-year deal by 12:00 BST so he can play against West Ham on Sunday.
The Arsenal midfielder, 21, completed a medical on Friday morning and Bruce said he would train before assessing whether he would feature in Newcastle's game at St James' Park.
The deal is in excess of £20m after a successful loan spell last season.
"We had to be patient but it was worth the wait," Bruce said.
"Where else can you find a 21-year-old who scored seven on the trot [on loan last season] and plays like him?