With pre-season tours underway for most top clubs across Europe, this is also the time for players to use the opportunity to try and force their respective clubs' hands and secure a move of their choice.
There have been a few players in the past who have refused to return to pre-season or go on pre-season tours as a form of protest to force their clubs to sell them.
Here are four players who missed pre-season with the pretext of forcing transfers:
4. Marcos Rojo
When Manchester United were looking for a centre-half in 2014, they targeted Argentine international Marcos Rojo following his impressive performances at the 2014 World Cup.
Sporting CP weren't ready to let him leave immediately, so Rojo handed in a transfer request and refused to train with the team. Manchester United legend Juan Sebastian Veron convinced his compatriot that United was the right move for him, and the transfer was finally completed in August.
3. Raheem Sterling
The English international had just had a good season for the Reds and was keen to join the Manchester side so as to play in the Champions League. The strike helped his cause as the Reds finally agreed to let him go for a fee of around 50 million pounds.
He has become one of the best players in the Premier League since his move, justifying his decision to leave.
2. Laurent Koscielny
Laurent Koscielny has been at Arsenal for nine years now and has been at the top of his game for almost all of those years. The Frenchman was of the opinion that the 2018/19 season would be his last with the club and he would be let go for free even though he has one more year on his contract.
The Gunners have refused to let him leave for free and as a result, Koscielny has decided to refuse to go for the pre-season tour in the hope that the club will cancel his contract.
1. Antoine Griezmann
Antoine Griezmann was keen to move to Barcelona in the current transfer window, despite having just signed a contract extension last year. The player announced just after the 2018/19 season ended that he would not be staying at Atletico Madrid next season.
With his move taking time to reach completion, Griezmann refused to appear for pre-season. He finally did get his move to Barcelona, after the two-time defending La Liga champions triggered his release clause.
Looking at four players who refused to join pre-season to force transfers