The former Manchester United captain accused his old club’s skipper of play-acting to influence referee Michael Oliver’s decision at Old Trafford.
Foden was shown a straight red card in the first half after kicking out at Fernandes during a clash near the touchline.
The Irish legend was unimpressed by Fernandes’ reaction to the incident and questioned his theatrics.
"We have to be fair and ask did the player give the referee a chance and Foden is a bit daft but so is Bruno here,” Keane told SkySports.
“If Bruno got sent off just for that we’d be saying Bruno was a bit daft and a bit silly.
"You can’t be rolling around. Bruno’s got to do better there. People saying there’s tension there, it’s a big game but you’ve got to after your teammates and the opposition players as well. Foden, I don’t think it’s a red card."