Bayer Leverkusen's Omer Toprak, Kevin Kampl sidelined with injuries

Bayer Leverkusen have been handed a double injury blow after defender Omer Toprak and midfielder Kevin Kampl both sustained muscular injuries in the club's 1-0 loss to Borussia Dortmund on Sunday.

Centre-half Toprak and holding midfielder Kampl both stayed in the dressing room at half-time and were replaced by Kyriakos Papadopoulos and Andre Ramalho by coach Roger Schmidt.

Examinations on Monday confirmed that both players are set for a spell on the sidelines, and will not be able to help Bayer Leverkusen as they fight to return to Champions League.

"Central defender Toprak picked up a groin injury against BVB and that means the defensive rock of the past few weeks faces a spell on the sidelines," a statement on the official club website read.

It added: "Kampl did not come back on for the second half against Dortmund and a medical examination on Monday revealed the Slovenia international has torn a muscle in his left calf."

On Sunday, Leverkusen not only lost Kampl, Toprak and the three points but also coach Roger Schmidt, who refused to leave the pitch when being sent off by the referee in the aftermath of Dortmund's goal in the 64th minute.

The German Football Association has opened investigations against Schmidt, and he could face a touchline ban or worse.

Bayer Leverkusen rank fourth in Bundesliga, and at the weekend travel to Mainz, the first team outside the European ranks. Schmidt's starters have won 35 points, and Sunday's rivals have won 33.