Ronald Koeman said on Tuesday he needs more time to instil his ideas after his poor start as Barcelona coach.
Barca face Athletic Bilbao on Wednesday, looking to reduce their 10-point gap behind La Liga leaders Atletico Madrid, who have also played one game fewer than the Catalans.
The pressure is already mounting on Koeman, whose future could become more uncertain when the club's new president is voted in later this month.
Asked when his methods will deliver better performances, Koeman said: "Little by little we are going to see it. We have tried to take the team forward and to prepare them for the championship but we have important players out injured and I have a squad I have not been able to change much. I need more time to impose my ideas."
Koeman confirmed midfielder Carles Alena will be allowed to leave, with the 23-year-old expected to join Getafe on loan.
But there are not likely to be many arrivals this month at Camp Nou, given the club's perilous financial situation.
"Every coach, every January is thinking about how they can improve their team," said Koeman. "I have made a plan of ins and outs. If it is possible or not depends on the club. If not, we continue with what we have."
Barcelona had to postpone training on Tuesday after two members of staff had tested positive for coronavirus.
Another round of tests was carried out on Tuesday morning but the club reported no further positive cases and training went ahead on Tuesday evening.
"We were calm," said Koeman. "There are things in life it is not possible to control."
Barca will be up against an Athletic Bilbao side playing their first game under new coach Marcelino Garcia Toral, the former Valencia boss appointed on Sunday after the sacking of Gaizka Garitano.
Bilbao sit ninth in La Liga, having won only six of their 17 league games this term.
"When you get the chance at a great club like Athletic, you have to answer quickly," said Marcelino on Tuesday. "Any football man knows what this club means in this league. It is an exciting project."