The 22-year-old started in a deeper role against Fulham on Saturday and set up Kai Havertz for the game's opening goal, but he was substituted after suffering a suspected back injury on the 76-minute mark.
Speaking to reporters after Saturday's 2-0 win against the Cottagers, Tuchel said: "I hope really that Mason is not a big thing and hopefully he can fully recover for Real Madrid."
Antonio Rudiger also missed the Premier League triumph over Fulham due to a minor injury, but Tuchel is optimistic that the German defender will make the cut on Wednesday.
Two goals from Havertz saw Chelsea strengthen their grip on a top-four spot in the Premier League table against Scott Parker's men, and they prepare to welcome Real Madrid to the capital following a 1-1 draw in the first leg. body check tags ::