The Argentina international was forced off inside the first 25 minutes of City's Champions League clash with Dynamo Kiev on Tuesday with an apparent dead leg and is now a doubt for the clash with United at the Etihad.
"It's very similar to a dead leg injury I have had before. I will have a test," Otamendi said.
"The blow wasn't that serious, but it was better not to continue and come off. The test, I hope it shows nothing and am hopeful I can be there on Sunday.
"That is a derby and I will have to be 100 per cent and try to win the Premier League game. It's a derby, we want to win."
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