The Blues released a short statement Thursday: "Chelsea Football Club has today agreed terms with Atletico Madrid for the transfer of Diego Costa. The transfer will be subject to the agreement of personal terms and a medical."
Per AS (via Sky Sports), the deal that has finally been agreed to is worth £53 million and should bring to an end the ongoing Costa saga that saw the 28-year-old effectively go on strike in Brazil over the summer.
As noted by Dominic Fifield of the Guardian, Atletico were keen to sign their former striker in the recent transfer window, although a deal wasn't done before the summer deadline.
Costa has spent three full seasons at Stamford Bridge, in which he left many Premier League defenders in a daze.
He earned the move to the Blues on the back of a brilliant season with Atleti in 2013-14. He epitomised the brash brand of football played under Diego Simeone at the Vicente Calderon, as the capital club secured a surprise La Liga triumph.
The momentum Costa built up with that succession of outstanding performances was carried into his debut term at Stamford Bridge.
Under Jose Mourinho, the striker started the campaign in magnificent form, bullying defenders, winning aerial battles and sticking the ball in the back of the net. He scored 20 times in the Premier League in 2014-15 and added another title to his collection.
The next season wasn't quite as prosperous for the player. Costa admitted in an interview with Matt Barlow of the Daily Mail that he was "overweight" at the beginning of the campaign, and that was reflected in his performances. The striker found his edge late in the campaign, although it was an underwhelming effort overall.
He preserved that edge in the 2016-17 season, though. While there was speculation about a possible January exit after a row with manager Antonio Conte, Costa rediscovered his best form, netting 20 times as Chelsea marched toward the Premier League title.
As reported by Ed Malyon of The Independent, it became clear Costa had no future at Stamford Bridge when he was excused from pre-season training. It's added Conte advised the striker he would be leaving via text message.
Atleti will need to channel the aggression of Costa, which can sometimes spiral out of control. The Spain international is not a player who is to everyone's taste, but when he's on your team, he's an ideal footballer to have in the squad.
It's unlikely many neutral supporters will miss Costa in the Premier League, as he did little to endear himself to the casual fan. Nevertheless, the unique physical challenge he poses to defenders makes him one of the most feared centre-forwards around and a force of nature many opponents will be glad to see the back of.