A bad challenge suffered in the first minute of Sunday's victory over Palermo has Kaka struggling to make next week's crucial Champions League second-leg date with Arsenal.
"I am on the receiving end of many blows," complained Kaka, "and I'm not the only one. The referees must do something about this."
Milan fitness coach Daniele Tognaccini, discussing Sunday's incident, added: "He took a kick that would've grounded a normal person for good."