Tuchel stated he would not alter England's current formation to accommodate both players, prioritising placing individuals in their optimal positions.
He noted last week that Bellingham, who has returned to the squad for the final international camp of 2025, currently holds an "edge" for the No 10 role.
The team is preparing for their match against Serbia, having already secured qualification for the World Cup.
Tuchel aims to maintain squad consistency and foster a "brotherhood" among players in the lead-up to next summer's World Cup.