The contract situation with Mateta is the latest twist to what has been a rollercoaster time for the Frenchman at Crystal Palace.
The 29-year-old has become a cult hero at the Eagles due to his trademark celebration where he kicks the corner flag to shouts of “boom” from supporters, while the striker also scored the winning goal in the final as Palace won the Conference League last season.
It has not always been smooth sailing for Mateta though.
The forward had a slow start to his Palace career but his trajectory was transformed under the guidance of former boss Glasner.
Mateta became one of the most reliable strikers in the Premier League and scored 46 goals in 109 games in all competitions under the Austrian.
That form led to interest in Mateta across Europe, and the contract standoff that has the club and the striker in the current situation.
Mateta has always been highly ambitious and made clear his desire to play for clubs at the elite level of the game, even during times early on in his Palace career when his form made it seem unlikely.
Alongside his aim to represent top clubs across Europe, Mateta has chased a place in the France national team and he achieved that goal in October last year before securing a place in the final 26-man squad for the World Cup.
When it seemed like Mateta would leave the club in January, Palace moved to sign Jorgen Strand Larsen as a replacement for a deal worth up to £48m.
The Norway striker made his debut for Crystal Palace in a win over rivals Brighton last season and Palace fans repeatedly chanted his name as they got behind their new striker in a show of support as Mateta’s time at the club looked to be over.
However, Mateta failed his AC Milan medical and remained at the club, being ruled out for about two months with the issue.
He was booed by some sections of fans when he returned in the last-16 tie against AEK Larnaca in March before he turned around the fan feeling with a goal in the final of the Conference League, and he ended the season with 16 goals in all competitions.
Mateta has been a key part of the most successful time in Palace’s history in which the club won the FA Cup, Community Shield and Conference League, but the current contract standoff threatens to leave a stain on his time at the club.