January 1st is the next official transfer window. No transfer can take place before then.
Probably a misunderstanding somewhere - he has definitely gone.
http://annualreport.mcfc.co.uk/financial-report/notes-to-the-consolidated-financial-statement
29 - Post balance sheet events
As at the date of signing the Directors’ Report, since the year-end the football registrations of Raheem Sterling (from Liverpool FC), Fabian Delph (from Aston Villa FC), Nicolas Otamendi (from Valencia CF) and Patrick Roberts (from Fulham FC) have been acquired. The football registrations of Karim Rekik (to Olympique de Marseille), Edin Dzeko (to AS Roma), Marcos Mesquita-Lopes (to AS Monaco) and Dedryck Boyata (to Celtic FC) have been sold. The net expenditure on these transactions was approximately £68.3m.