Last summer, Chelsea allowed a few of their players to join direct Premier League rivals.
Mason Mount left Stamford Bridge for Manchester United, Kai Havertz joined Arsenal and Mateo Kovacic signed for Manchester City.
Last season, Chelsea were really made to pay for allowing Havertz to move to Arsenal. The German arguably improved them and managed to score two goals against his former club.
In total, Havertz came up with 20 goal contributions in 37 Premier League appearances.
A repeat could have happened with Conor Gallagher after he was linked with more than one English club, but he is now set to join Atletico Madrid instead. At one point, though, it looked like Gallagher’s move to Atletico could have collapsed.

Darren Bent claims Chelsea would not have sold Conor Gallagher to Tottenham
One of those clubs who were heavily linked with Gallagher were Chelsea’s London rivals Tottenham Hotspur.
However, with Atletico agreeing a £34m deal with Chelsea for the midfielder, as per Sky Sports, a move to Ange Postecoglou’s side will not be happening.
Darren Bent doubts Chelsea would have sold to their fierce rivals anyway, though he thinks he could have been a really good signing for them.
Speaking on talkSPORT, the former Tottenham striker said: “There’s no way on the planet Chelsea were letting him go there. No way. Yeah, I think he would have made them better. Listen, you have a Conor Gallagher in your team, you are not all of a sudden title contenders, but you know what you are going to get with him.
“I think when you sign a new player, you know they have got to be a good character. He’s obviously that. He is going to work his absolutely everything off. So that’s another thing there. They are the basics — being a good character and working your everything off. He can play. He is a good player.”
While he was a key player for them last season, Chelsea feel there isn’t a need to replace Gallagher.
Chelsea fans would have fumed at owners
Coming through Chelsea’s academy, Gallagher is obviously a popular figure among supporters at the club.
Bearing that in mind, supporters would have lost it with the Chelsea owners had they sold Gallagher to Tottenham.
It is a big season for Todd Boehly and Co, who have made some big decisions, such as replacing Mauricio Pochettino with Enzo Maresca.
The Italian is still quite an inexperienced manager, who is already finding problems with this Chelsea side. For example, Maresca identified Chelsea’s high line as an issue in the team’s recent 2-1 defeat to Real Madrid.
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