The Dutch defender, who was played at centre-half, featured as a second-half substitute for the 7-0 thumping.
Sandler said, "I always play there. Honestly, I have never been in the midfield. Why now? I stood there during the training session. Sending passes. Since I've been here, I try to develop as a central defender.
"Vincent Kompany helps me enormously. I learn a lot from him.
"I do not know if I will get another chance again soon. I especially want to be completely fit first."