The Ivory Coast striker was signed by the German Bundesliga club from Ajax in the summer to replace Erling Haaland who had departed for Manchester City. However, a few weeks into his time at the club, he was diagnosed with testicular cancer and as such, never got to make his official debut for the club.
Borussia Dortmund have continued to support him in his treatment despite the uncertainty of him returning to the club or to active football. But in a promising turn of events, Haller has strapped on his football boots once again.
Ajax manager Alfred Schreuder revealed this in his pre-match press conference ahead of their UEFA Champions League match against Liverpool on Wednesday. “He asked us if he could come and train because he was rehabilitating here,” Schreuder said. “Then it is of course wonderful that he can be there for a while.
“He was able to train on a different pitch to help his recovery.”
Haller, who was coming off the back of an incredible season which saw him score 34 goals for De Godenzonen across all competitions last season, was signed for £31 million by Dortmund. About two weeks into pre-season, he began feeling unwell and the tests revealed a malignant testicular tumour.
The 28-year-old shared some insight into his recovery in an interview with UEFA. The former West Ham United striker said he sometimes spends five days at a time at the hospital, ‘where I am hooked up 24/7’ and cannot get out of bed while receiving treatment.
A two-week rest period follows after that treatment, which he claims is just one phase of the entire process. “I have to do that four times,” he said. “Four phases of chemotherapy lasting roughly three weeks each.
“After that, depending on how my cancer is progressing and how it is spreading, I may be forced to undergo surgery.
“A lot of people are asking me when I will be back, but there’s a lot to take into account so it’s hard to give them a straight answer.”
His treatment has finally progressed to the level where he can train and now, he has an answer for those who have been enquiring about his return. “I’m lucky enough to feel well,” he said. “I am physically able to work, I feel fine from both a mental and a physical point of view, which is of course helpful to fight this disease. I have a timescale in mind.
“If I’m lucky enough not to need surgery, things can go very quickly. Three weeks after the final phase, checks are made to see what stage the metastasis is at, and whether you require surgery or not.
“If I don’t need an operation, with the way I train, I’d like to think that I will be in good condition at the end of those three weeks.”