Former Bayer Leverkusen star Michael Ballack has urged the club to focus on securing another top-four Bundesliga finish, not challenging Bayern Munich or Borussia Dortmund for the title.
Leverkusen have finished in the Champions League places in each of the past four seasons, but last term ended 18 points behind Dortmund and a further 10 adrift of the champions.
Ballack spent five years at the club across two spells, including an agonising 2001-02 campaign which saw Leverkusen finish runners-up in the Bundesliga as well as losing the Champions League and DFB-Pokal finals.
Roger Schmidt's side begin the new campaign at fellow Champions League hopefuls Borussia Monchengladbach on Saturday, but they will do so without two key men.
Captain Lars Bender is missing with an ankle injury sustained in the Olympic final with Germany, while last season's top scorer Javier Hernandez is out with a broken bone in his hand after falling down the stairs.
Ballack is optimistic over Leverkusen's chances for 2016-17, but warned the club against being overambitious.
"I'm cautious because I have seen the last few years and have seen the quality of the players," he told Omnisport.
"If everything works well and everything harmonises, they can beat Bayern as well. That's clear. No question.
"But over an entire season I'm not sure if they can play at the same level as Bayern or Dortmund. Even in the last season they had ups and downs.
"They were in eighth, ninth place, and almost slipped. There was even a discussion about the trainer, but Leverkusen is a club which remains calm in such situations.
"[Sporting director] Rudi Voller is a man who knows the league and the club very well. And they are back on track. In the end they finished the season with a Champions League spot. This is not the optimum, but for the club the goals ware achieved. And here they should set their goals again.
"After that you have to wait [and see] how the season proceeds. But I think the guys can assess themselves very well and shouldn't require unrealistic things from themselves.
"If they look good after the winter break, they will adjust their goals. But currently before the start of the season, Bayern is far away from the other clubs."