The Brazilian has featured in midfield several times under Rafa Benitez, and Mikel claimed that adapting to the different combinations was making him question his game.
"It affects you because I've been here for a long time," Mikel told Chelsea's official website.
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"It's just a lot. I think, psychologically as well. You think, 'If I'm playing today, who am I going to play with?' - because they're all great players."
The 25-year-old returned to the Blues side on Boxing Day after serving a ban for using insulting language towards referee Mark Clattenburg, an incident that saw the official accused of racially abusing the player, and Mikel was just delighted to put the incident to bed and get back to playing.
"It was good to come back into the team and play against Norwich," he added.
"I had my ban, three-game ban, and obviously I've been training with the team. But, as a football player, you want to be out there playing games."