Chelsea join Man United and Man City in the race to sign Diogo Costa

Chelsea are set to have a busy summer transfer window once again in order to strengthen their squad.

Enzo Maresca made some high-profile signings like Pedro Neto, Joao Felix, Jadon Sancho and others in the summer transfer window last year.

The Blues had an impressive start to the season but since the start of this year, they have failed to fulfill their potential and are currently fighting to finish in the top four of the Premier League to qualify for the Champions League next season.

The…