Bayern Munich will be without Germany defender Mats Hummels for Tuesday's Champions League clash at home to Benfica, which could be Niko Kovac's last game in charge as head coach.

According to Sky, magazine Kicker and Germany's top-selling daily Bild, Hummels has dropped out with a stomach bug, leaving head coach Kovac with only 13 fit out-field players for the visit of Benfica.

Hummels has been laid out by gastroenteritis, which has also hit his wife Cathy and 10-month-old baby son Ludwig.

With the experienced centre-back out, Niklas Suele and Jerome Boateng are set to partner up against Benfica.

Hummels is the latest casualty on Bayern's walking wounded list, which includes James Rodriguez, out with a torn knee ligament, Kingsley Coman and Thiago Alcantara (both ankle injuries) and Corentin Tolisso (knee injury) also sidelined.

Bayern need only a point to book their place in the last 16 of the Champions League.

However, Kovac badly needs a moral-boosting win in Europe with Bayern nine points behind leaders Borussia Dortmund in the Bundesliga table, leaving Kovac under intense pressure to turn things around.

After Saturday's embarrassing 3-3 draw with Fortuna Duesseldorf, when Bayern threw away a 3-1 lead, Bayern president Uli Hoeness has said Kovac's job is safe only until the Benfica game.