Eintracht Frankfurt defender Makoto Hasebe is set to miss several weeks due to a knee injury sustained in his side's midweek 3-2 loss at Tottenham.
Hasebe has been increasingly important for Frankfurt in recent weeks. Manager Oliver Glasner said his loss "would be a challenge".
Glasner said Hasebe had "torn a ligament in his knee and will be out for several weeks."
"It looks like he won't be playing too many more games in the autumn."
At 38, Hasebe is the oldest player in the Bundesliga and had previously been periodically rested.
Despite his age, Frankfurt offered him a new contract on Wednesday, saying it was up to the former Japanese international whether he wanted to play on for Frankfurt or not.
Hasebe, who previously captained and played 114 games for Japan but retired from international duty in 2018, could be out until the World Cup break in mid-November.
Hasebe is one of several injured Frankfurt defenders. Glasner appealed to his players to "keep their egos in check" and play where required while the club struggled to get enough players on the park.
"It's important that we're not dependent on a 38-year-old Makoto Hasebe. It's about taking responsibility and accepting it," Glasner said during the pre-match press conference ahead of the match with Leverkusen on Saturday.
"That's what I expect from my players."