Sunderland manager Steve Bruce beat off competition from several other top flight teams for the 25-year-old who began his career at Charlton Athletic before moving to Brentford.
"Michael is one of the country's premier central defenders and I have had my eye on him for a while," Bruce told the Sunderland website.
‘Chelsea have to qualify for the Champions League for this season to be a success – they showed that they have the players to perform at a high level, they need a win quickly now’ Blues legend’s fears over recent bad run
'I’d probably pick Cole Palmer alongside Bellingham and Rice in there at the moment. For me, Declan Rice is good enough to play that central midfield role on his own' Thomas Tuchel advised to DROP Manchester City star by England legend
