The 34-year-old was omitted from Manchester United's squad for the game against City, which the visitors comfortably won 2-0 thanks to Eric Bailly's own goal and yet another Bernardo Silva strike at Old Trafford.
Cavani had started alongside Cristiano Ronaldo at Tottenham the week before - netting his first Premier League goal of the season to help United cruise to a 3-0 win - but beleaguered United boss Ole Gunnar Solskjaer revealed before kick-off against City that "we've had a couple of issues since Italy [United played Atalanta in the Champions League on Tuesday], Edi has been one of them."
The Uruguayan has now revealed that he's been struggling with a tendon injury for a number of months, telling local newspaper El Observador (via United's official site): “The issue was like this. Before starting the season, I had discomfort in the tendon".