Sebastien Haller, a striker for Borussia Dortmund, has been diagnosed with a testicular tumour.

The Ivory Coast international, 28, joined the Bundesliga side from Ajax earlier this month as a substitution for Erling Haaland, but will now most likely miss the start of the season.

According to a statement on the official website of Borussia Dortmund, the player had complained of feeling ill.

Also read: Why Paulo Dybala is joining Roma on a free transfer

During the course of the day’s examinations, “a tumour was finally discovered in the testicles during the course of the day. During the coming days, further examinations will take place in a specialised medical centre.”

“Borussia Dortmund asks that the privacy of the player and his family be respected and that no questions be asked. As soon as we have further information, we will inform you in consultation with the player,” the statement adds.

Sébastien Romain Teddy Haller was born on 22 June 1994.

Also read: Cristiano Ronaldo transfer: 3 top clubs that rejected him and why

Haller began his career with Auxerre before joining Utrecht on loan in 2015 before joining on a permanent basis. After two years in the Netherlands, he went to Eintracht Frankfurt, where he won the DFB-Pokal in 2018. Haller’s performances piqued the interest of West Ham United, who signed him in 2019 for a club-record fee of €49.8 million (£45 million).

Haller returned to the Netherlands in 2021 after a disastrous period in England, joining with Ajax for a club-record fee of €22.5 million (£18.8 million). He won the Eredivisie and the KNVB Cup in his first six months. During the 2021-22 season, Haller became the first player to score in seven straight UEFA Champions League matches.

Also read: Robert Lewandowski has a message for Barcelona ahead of Miami game | Watch

Haller, who was born in France to a French father and an Ivorian mother, represented France at the youth level before moving to the Ivory Coast in 2020. He scored his first international goal against Madagascar and will represent his country at the Africa Cup of Nations in 2021.