After tests, City have confirmed that the Brazilian has a 'medial collateral ligament injury'. The club has given no timeframe on his likely return to action, but early estimates place the expected layoff at anything between one month and three months.
Jesus has scored eight Premier League goals this season, albeit none since mid-November, and it is a second bitter injury blow for him during his young City career to date.
Last season, a broken foot left the former Palmeiras starlet sidelined for a total of 13 games in all competitions, picking up the injury in just his third Premier League start.
There is better injury news regarding Kevin de Bruyne after he was brutally taken by Crystal Palace winger Jason Puncheon during the 0-0 draw at Selhurst Park.
While a serious problem was feared after the Belgian was stretchered from the field, The Times has reported the diagnosis as a 'heavy knock'. De Bruyne could therefore be back by the time City face Watford on Tuesday night, although a return in the FA Cup at the weekend is plausible.
There is also the possibility that manager Pep Guardiola could hand De Bruyne a short break to help him recover and rest by also leaving him out of the cup tie against Burnley.