Former Blackburn Rovers loanee Matt Grimes
Grimes signed on a season long loan deal before the Cook news broke, and as a young central midfielder, the pressure is on.
Fortunately he is not a player fazed by such pressure, in his own words, speaking to the FA website earlier this year.
He said: "You always want to play in front of a crowd in front of noisy, great fans but it's something that you can't let take control of you.
“I'm not one to get influenced by a crowd or let my emotions get controlled by fans. Some people let it get control of themselves and put in a daft tackle but it's never really affected me.
“You just have to trust in yourself and not let things manipulate what you are trying to do. If you're given a task on a Saturday to go and just mark one player you can't let people distract you from the job.
“You just need to keep your head focused and not let anyone get in amongst you.”
Blackburn Rovers' Matt Grimes in action
These level headed qualities will stand Grimes in good stead at Leeds, where players struggled early last season to play in front of a home crowd, failing to win at Elland Road until gone October.
It is off the pitch where Grimes will need to stay focused too, if he hears whispers from fans on social media that he is not up to the task, if results do not go Leeds' way.
Lewis Cook is a much loved figure at Leeds as an academy product and filling his boots is going to be a difficult job. Grimes though may just be up to the task.
Lewis Cook of Leeds United in action with Henri Lansbury of Nottingham Forest