Borussia Dortmund should be relieved to have kept Pierre-Emerick Aubameyang as he is their only irreplaceable player, according to former coach Ottmar Hitzfeld.
The 28-year-old, who finished as top-scorer in the Bundesliga last season with 31 goals, has been heavily linked with a move away from Signal Iduna Park during the close-season.
No transfer has materialised despite reported interest from the Chinese Super League, Chelsea and AC Milan and Dortmund have insisted they will not consider any more approaches.
Hitzfeld, who spent six years as head coach of BVB, says current boss Peter Bosz should be delighted to be keeping a player who "makes up 20 per cent" of his side's potency.
"For Peter Bosz, Aubameyang is a life insurance company," Hitzfeld told Eurosport. "He is the most important player for Borussia Dortmund. You could replace any player, but not Aubameyang.
"He makes up 20 per cent of Borussia Dortmund. He is a top striker, he creates chances to score out of impossible situations, he can also do something by himself and is not only dependent on his team-mates.
"If [chief executive Hans-Joachim] Watzke says he will stay until the end of the season, then this is a clear sign. It's a challenge to Bayern Munich: we keep Aubameyang to become German champions!"
Dortmund finished third in the Bundesliga last season, 18 points adrift of champions Bayern Munich, but they defeated Carlo Ancelotti's side in the DFB-Pokal semi-finals en route to lifting the trophy.
And Hitzfeld, who won two league titles and the Champions League during his time in charge, expects them to challenge Bayern all the way during the 2017-18 domestic campaign.
"I am still convinced that Borussia Dortmund will be the biggest competitor for Bayern Munich. The DFL-Supercup [on Saturday] is a first comparison of strength," he said.
"The club have ambitions in their whole environment. The team has stayed together, [Mario] Gozte is coming back again and hopefully he stays healthy. This also would be an absolute reinforcement for the team, because he is one of the biggest and best players that Germany have in a technical sense.
"So, Dortmund have ambitions."
