Borussia Dortmund coach Thomas Tuchel attempted to temper expectations ahead of the 2015-16 season, conceding "we're not where we want to be yet".
Tuchel, who was announced as Jurgen Klopp's replacement in April, has been putting his new squad through their paces in the Swiss town of Bad Ragaz, and he has conceded Dortmund need to improve if they are to improve on their disappointing 2014-15 campaign.
Dortmund dropped to bottom spot in the Bundesliga standings just after the winter break last season but Klopp helped steer them back to seventh-place finish.
But Tuchel still wants defensive improvement from his team ahead of their first competitive fixture - a UEFA Europa League qualifying first leg on July 30.
"We're not where we want to be yet. There is still a lot of work to be done," he said, according to Dortmund's official website.
Tuchel added: "We're still in the process of getting to know the players' strengths and the positions in which they feel comfortable."
Dortmund have two more friendlies before that Europa League qualifying tie - against either Shakhtyor Soligorsk or Wolfsberger - with a hit-out versus Luzern set for Tuesday and a clash with Juventus on Saturday.
Tuchel is also looking to keep his players fresh ahead of a long campaign.
"It is a case of less is more [at training]," the 41-year-old coach said.
"We need to be careful not to overdo it. In this respect all of us - including the coach staff - must be disciplined.
"We need to stay fresh enough to perform well in the friendlies."
Dortmund's Europa League tie will be followed by a DFB Pokal match against Chemnitzer on August 9 before their Bundesliga opener versus Borussia Monchengladbach on August 16.
