The Skeggy local rejected the move at the last minute, instead prefering to battle for his place at the Stadium of Light.
In the end that proved a wise move as Oster fought his way into Mick McCarthy's thoughts and is now a regular in the 16.
With his current contract ending in the summer, Oster is keen to tie himself down to another deal in the North East and says talks are already underway.
"We're talking about a new contract at the moment," Oster said.
"This is a club that is going places and I want to be a part of that. We're looking at the top two."