A failed drugs test has revealed Eintracht Frankfurt captain Marco Russ has a tumour, his club has confirmed, adding that he still wants to play in Thursday's relegation play-off match.

The 30-year-old centre-back was informed of the diagnosis on Wednesday, on the eve of Frankfurt's relegation play-off, first-leg, at home to Nuremberg.

His club has not disclosed the location of Russ' growth.

"He was very composed, as was his wife, when he informed us," Eintracht's chairman Heribert Bruchhagen told Frankfurt radio station FFH.

"Marco told the coach, during the course of the evening, that he feels ready to play the game."

Frankfurt said Russ had been informed that he had tested positive after a test by the National Anti-Doping Agengcy (NADA).

The test had revealed a noticeable increase in value of the pregnancy hormone HCG and the player then saw a urology expert who diagnosed a "severe tumour".

As required by Germany's Anti-Doping Act, the Frankfurt prosecutor's office raided the hotel where the Eintracht team stayed on Wednesday night, looking for evidence of hormone treatment.

At that time, the tumour had not been revealed.

"We had to act," a spokesman told SID, an AFP subsidiary, and nothing suspicious was found during the raid.

In a statement, the club said doctors have given Russ the green light to play when Eintracht host Nuremberg for a place in the Bundesliga next season with the return leg away next Monday.

Russ came up through the Eintracht youth academy and has spent his entire career with Frankfurt apart from a season and a half with VfL Wolfsburg between July 2011 and January 2013.