Marco Russ has been diagnosed with a severe tumour disease, Eintracht Frankfurt have announced.
Frankfurt were notified Russ had failed a drugs test due to high levels of the hormone human chorionic gonadotropin (HCG).
The club subsequently initiated internal medical examinations which revealed the abnormal values were a result of a severe tumour disease, with the National Anti-Doping Agency (NADA) requesting further analysis.
"Eintracht Frankfurt has today [Wednesday] been notified of a positive drug test by Marco Russ by the anti-doping commission of the DFB," a Frankfurt statement read.
"In the finding there is a striking increase in the value of growth hormone HCG.
"We immediately implemented an internal examination, with a urology expert, in the late afternoon which gave a specialist medical finding of severe tumour disease, which explains the increased values.
"This finding was unfortunately confirmed in the evening by the immediately initiated blood tests from a biochemical institute.
"NADA had itself noted that the high value of the growth hormone can also be an indication of a disease and has suggested a clinical examination to protect the player."
Russ remains hopeful of participating in the Bundesliga relegation play-off against Nurnberg, the first leg of which is on Thursday.
"Despite the … diagnosis the player declared himself ready to play, which was confirmed by the medical staff," the statement added.
