4 players Chelsea regrets selling
#3 Diego Costa
Diego Costa, the Brazil-born Spanish footballer is currently at Atletico Madrid. Despite having three great seasons at Stamford Bridge, he was forced out of the squad by Chelsea's former boss Antonio Conte in 2017.
Costa scored 58 goals in the 120 appearances for Chelsea, and also played a pivotal role in Chelsea's last league title victory. But these stats did not prove to satisfy Conte, and he was forcefully sent back to his former club Atletico Madrid.
As Morata is far from being effective, and has not proved to be a worthy striker, Chelsea has duly missed the services of Diego Costa.
All stats via transfermarkt