Neil expressed his desire to leave Wearside on Friday morning and said his goodbyes at the Academy of Light before travelling to Staffordshire to finalise the move.
Sunderland’s Sporting Director Kristjaan Speakman has said Neil signed an improved 12-month rolling contract at the Stadium of Light earlier this month, and that a new proposal was made after the Scot expressed his desire to leave.
“First and foremost, we want to thank Alex for his contribution to Sunderland AFC,” said Speakman in a club statement. "The impact he made is clear and he played an integral role in our promotion last season.
"Despite signing revised terms earlier this month and receiving an offer to further improve his contract on Friday, Alex felt this was an opportunity that he wanted to pursue.
"We are extremely disappointed by his departure, but we ultimately respect his decision and we wish him well. The process to appoint a new Head Coach is underway and we will provide a further update to our supporters shortly.”
Here, though, we take a look at the early contenders to replace Neil at the Academy of Light:
1. Roy Keane
Roy Keane was interviewed for the Sunderland job before Alex Neil appointed it but rejected his former club's approach. Photo: Ash Donelon
2. Tony Mowbray
Tony Mowbray is one of the favourites to take the Sunderland job and has worked closely with head of recruitment Stuart Harvey when the pair were at Blackburn Rovers. Photo: Harriet Lander
3. Robbie Fowler
The former England striker through his hat into the ring after being tipped for the job by ex-Sunderland man Stephen Elliott. Photo: Shaun Botterill
4. Shaun Dyche
Shaun Dyche is out of work after leaving Burnley last season. Photo: George Wood