RB Leipzig head coach Ralph Hasenhuttl has revealed the club are still awaiting a proper diagnosis after striker Timo Werner was forced off against Besiktas.
Werner's 32nd-minute withdrawal was put down to the noise at Vodafone Park during the Champions League clash.
The 21-year-old attempted to counter the wall of sound by wearing earplugs, which were believed to have caused the issues that prompted his withdrawal.
But while Hasenhuttl added further information by confirming Werner suffered circulation and breathing issues, he revealed the club are still awaiting concrete information.
"There is no exact diagnosis yet," he said. "He has played a lot recently; that could have also caused the problems."
Hasenhuttl praised his striker for flagging up the problem and asking to be withdrawn, adding: "That was good and is better than if he had been on the field until the end."
Leipzig clearly felt his absence on Tuesday night as they fell to a 2-0 Group G defeat in Istanbul.