The Champions League semi-final tie is evenly poised at 1-1 after Real fought back in the first leg in Spain.
And Tuchel is still weighing up what he'll do to help his side reach the final.
"I will make my decisions very late like I usually do," said Tuchel.
"I have my ideas in my mind, but I'm too long in the business that I also know anything can happen in the last training session, or a situation can even change my mind.
"We need to wait. I need another sleep, and tomorrow I will decide on the line-up. I will give it to my team first, but what is sure is we played a good match with the line-up we had in the first game. It was a strong performance, and from that view there is no reason to do too many changes."