I thought that Osman played his part against Norwich.
He started on the left, with Gibson and McCarthy in the centre; Osman - Gibson - McCarthy - Mirallas. Everton had little possession. Gibson had little influence in midfield and Osman saw very little of the ball. Martinez could have changed this formation at half time - or before - but persevered with it until Norwich scored.
After an hour, he brought on Barkley to support Lukaku and Deulofeu to play right wing. Osman came into centre midfield as Gibson dropped back to centre half; Mirallas - Osman - McCarthy - Deulofeu. Osman took control of midfield as Everton came back into the game. And it was Osman who got the equaliser.
In extra time, Naismith came on for Mirallas, and Osman switched back to the left side; Osman - Naismith - McCarthy - Deulofeu. Norwich then gained more possession but could not score.