Pizarro, who joined Chelsea on a free transfer from Bayern Munich in the summer, said: "Of course Cisse kicked me and if I hadn't pulled my leg away I'd have broken my leg.
"I was lucky that I did pull my leg away but I still have the mark there. He cut me and you could see that my sock was cut as well."
Royals boss Steve Coppell criticised Pizarro for falling to the ground in spectacular fashion following the tackle.
"Football in England is a bit more direct than in Germany and the ball goes to the strikers a lot faster. There is not as much passing in midfield but it's as tough as in Germany. It's interesting but I like it."