The Magpies had to adjust when Dan Ashworth told them he wanted to go to Manchester United.
While he has since gone to Old Trafford, highly rated Mitchell is now set to lead the transfer charge this summer and beyond.
On transfers, he said: "Shorter term, transfer window I always say how can we make the team better. We make the team more set up to win. How can we align the club more to the way the coach wants the team to develop over time. That is the challenge this window.
"We have some really great components. You have to be a little more strategic because the elements you are looking for might be one or two positions not a whole total rebuild.
"We have made this big leap to this level so it is about getting the small decisions right over time. Not making those big decisions and destabilizing what we've already built. We have some really exciting foundations."