The former Ajax forward was optimistic after starting the process of getting well, but the team is being cryptic about whether they will hunt for a replacement.

Sebastien Haller, a striker for Borussia Dortmund, has finished the first round of his therapy after learning that he had a testicular tumor this week.

After training on Monday, the former Ajax forward reported feeling unwell. Subsequent testing discovered a tumor, 

Haller tweeted a photo of himself in a hospital bed on Thursday along with a favorable update on his health.

Haller signed a four-year agreement with Dortmund from Ajax earlier this month for an estimated £27 million,

 but his diagnosis has caused the club's transfer plans to fall apart because he will be sidelined for an unforeseen amount of time.

Although he acknowledged that life without the Ivory Coast international could be difficult for the Black and Yellow,

Dortmund CEO Hans-Joachim Watzke remained mum on whether the team would hunt for a temporary solution before the transfer window closed.

"It might be uneven. Watzke said to GOAL Germany on Friday, "But we mustn't use that as an excuse in any way; we have to take it as a challenge.

The midfielder, who has earned 15 caps for the Ivory Coast and scored four goals for them,