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 morale-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.