Bayer's Bender fit to face Atletico Madrid
Battling an ankle injury, the Germany international is back in training and a chance to start against the La Liga giants.
Leverkusen coach Roger Schmidt, whose team lead the tie 1-0 heading to the Vicente Calderon, was unwilling to give too much away.
"He is doing well. He could train the last two days without pain," he said on Monday.
"I will not announce the line-up today, but he is fit to play."
A goal from Hakan Calhanoglu in the second lifted helped Leverkusen to their victory at home.
Atletico are winless in their past four games in all competitions, but Schmidt is still wary of Diego Simeone's men.
"Of course we know that Atletico [are] different at home and that they are very strong," he said.
"One-nil is a good result, but tomorrow we must outdo ourselves to reach the next round."