WARSAW, Poland - Bayern Munich must make sure they bring in top players every season to stay competitive and ease the pressure on an ageing squad, Poland captain Robert Lewandowski has said.
Lewandowski, with the national team for friendlies against Uruguay on Friday and Mexico on Monday, also told Reuters in an interview that Bayern's first-choice players need back up.
"We shouldn't delude ourselves. Each club needs to get a top player every two or three years to refresh the team, to bring some new blood, new quality," he said.
After a stuttering start to the season, Bayern sacked their Italian coach Carlo Ancelotti and brought back 72-year-old Jupp Heynckes for his third spell in charge and the move has worked.
Since Heynckes returned on October 14, the club have won their seven matches in all competitions, reclaiming top spot in the Bundesliga after falling behind RB Leipzig and Borussia Dortmund.
They have also reached the last 16 of the Champions league.
"At this point we really have a good team, but it is known that players are getting older," added Lewandowski. "We are succeeding (in replacing them) today, because we have a young Josh Kimmich, who is really good at his new position and shows that a young player can be a replacement for such an experienced and wonderful one as Philipp Lahm."
The 22-year-old Kimmich, who was a central midfielder, has replaced retired former Germany captain Lahm as Bayern's starting right back and has become an integral player in that position for club and country in just a few seasons.
However, Lewandowski feels his recent injury problem may have been down to having to play too much without adequate cover at Bayern to give him the rest his body needs.
The 29-year-old came off after scoring just before halftime in the home win over Leipzig in the Bundesliga on October 28 with a muscle problem he feels may have been prevented.
"I had a minor injury. At the same time, injuries to other players who could not play at all meant I did not have an opportunity to rest or play for a shorter time," he said.
"Sometimes even playing 20-30 minutes less in a game or just missing a game means everything comes back to normality. Maybe my injury was due to the fact that there was no time to rest."
The Poland striker became the first player to score 16 goals in a single European qualifying campaign for the World Cup and finished as the continent's top scorer en route to Russia 2018.
His sparkling performances helped his country seal their first World Cup spot since the 2006 tournament in Germany and they will be relying on him to excel at the finals.
There has been media speculation that Lewandowski is unhappy with Bayern's transfer policy but his focus is on the World Cup.
"The tournament is so important that no one will think about changing club in that time," he said.