Christensen’s contract expires at the end of this season and he has not signed a new deal, although Chelsea have signaled their intentions of wanting him to stay.
Rumors this week indicate that Christensen is preparing to join Barcelona as a free agent at the end of the season.
Speaking at a media conference ahead of the Blues' Premier League fixture at Norwich City on Thursday, Tuchel said when asked about Christensen's future: "It's in doubt, no?
"We hear the rumours and the situation with Andreas has clear for many weeks and we are not happy about it, because we think that it's best for him to stay and we rely heavily on him.
"He did not sign yet, so you cannot not communicate. This is also a signal to us and communication from his side is that he did not sign until now, so we have to consider the possibility that he leaves us.
"Will we like it? No. Will we live with it? Yes. Things are not personal [and] never should be personal, but this can happen and I have no further information."
Christensen is one of Chelsea’s longest serving players, having joined the club as a teenager in 2012 before making his first team debut in 2014.
The 25-year-old has had to bide his time before becoming a regular at Stamford Bridge, spending two years on loan in the Bundesliga with Borussia Monchengladbach between 2015 and 2017.
The Denmark international has since become an important part of the Chelsea set-up and has made 26 appearances across all competitions this season.
Christensen was part of the Chelsea sides that won the Europa League in 2019 and the UEFA Champions League last season. He has also added the UEFA Super Cup and FIFA Club World Cup to his list of laurels at Stamford Bridge this term.
