Sunderland AFC news: Manchester City 'set to sign' Cats youngster as ex-striker questions selection call
The Black Cats youngster has predominately played as a left winger in the early stages of his career, while he's also been capped by England at youth level.
And according to Sun Sport, Spencer's potential has alerted City, with the Premier League champions looking to bolster their home-grown talent.
The Citizens would have to pay a compensation fee for the youngster, which reporter Alan Nixon claims is around £200,000.
While Spencer's departure may come as a long-term blow, Sunderland's main focus is on winning promotion from League One.
Following their 1-1 with Oxford on Saturday, the Black Cats slipped five points adrift of the automatic promotion places, albeit with two games in hand on second-place Barnsley.
After the game at the Kassam Stadium, some fans questioned Jack Ross' team selection and substitutions, including former Black Cats striker Stephen Elliott.
"Gutting to lose a goal in last few minutes. Will feel like a loss. 2nd goal so important." tweeted the ex-Republic of Ireland international.
"IMO McGeady should always stay on pitch (unless knock picked up). Can’t dwell on it though as the games are coming thick and fast. #safc"
He added: "Luke O Nien got be wondering what he has done wrong. Is he an easy option to leave out as he seems like a nice happy guy. If I was him I would be banging door down to play. Is that in his nature? Been best player for weeks then gets dropped for last two games! #safc"