RB Leipzig coach Marco Rose admits Timo Werner could leave in January.
The former Chelsea striker has struggled for minutes this season and is being linked with a return to England. Werner has concerns about missing Germany's Euro2024 squad.
West Ham and Manchester United are among Prem teams watching developments.
Rose told Sky Deustchland: In the end, the principle of performance counts.
"Each player must accept the competition. Now it's a question of deciding: do I accept my situation and fight? Do I want to change?"