Villarreal will be without Cristian Zapata, Cani, Marco Ruben and Marcos Senna for their Group A meeting with Manchester City, while Javier Camuñas is doubtful.
These injuries are in addition to Giuseppe Rossi, who is out for six months, after knee surgery earlier this week.
The most serious of the other injuries appears to be to Zapata, who strained a ligament in his right knee during Saturday’s 2-0 Liga win against Rayo Vallecano, an injury which is likely to sideline him for five weeks.
Cani is expected to be out for seven days more having sustained the same injury at the weekend, when forward Ruben strained a left adductor muscle. Senna will miss the Manchester City match in order to rest an ailing left hamstring, while Camuñas will be given a late fitness test on his bruised right fibula.