According to reports, Borrusia Dortmund was interested in taking the young player on a season-long loan this summer and has already agreed on a personal deal with him.
Chelsea on the other hand is doing everything possible to block Callum's exit offer and waiting for other potential offers before considering the options.
Just last week, Chelsea boss, Tuchel, gave an update on the 20-year-old;
"There’s always room for improvement here in training,’ said Tuchel.
"It’s hard to argue that he needs regular game time to improve his level. At the same time, it’s not only about letting players go. If we want to compete in all competitions, it’s also about numbers.
"You need a squad of 20 to 21 players. I have the feeling that Callum decided to fight for his place here. He had a very good pre-season. The door is always open to sneak through. At the moment, there is no loan."
