4 players Chelsea regrets selling
#2 Kevin de Bruyne
Kevin De Bruyne has been one of the best playmakers in recent times. He has also been adjudged as Manchester City's Player of the Year twice, in 2016 and in 2018. De Bruyne was drafted in by Chelsea for £7 million during the 2012 transfer window.
He did not get many matches to play due to the presence of established stars in the team, and was loaned to Werder Bremen. With the termination of his loan spell at Werder Bremen, he moved to Wolfsburg FC on a permanent transfer for £18 million in 2015.
After having a great outing with Wolfsburg, he was acquired by Manchester City for a hefty sum of £55 million. He has proven to be worth every penny, and has been flawless in City's colours.
Chelsea has been nowhere close to getting De Bruyne back, and they badly regret underestimating the Belgian show stopper.