Ilkay Gundogan is concerned Bayern Munich's continued dominance of the Bundesliga will make German football less appealing to an international audience.
Manchester City midfielder Gundogan won the Bundesliga with Borussia Dortmund in 2012.
But Dortmund – who face City in a Champions League quarter-final first-leg on Tuesday – have not won the title since.
Bayern are closing in on a ninth consecutive domestic crown after beating closest challengers RB Leipzig 1-0 on Saturday, a result that came even as star striker Robert Lewandowski was injured.
Dortmund are usually among Bayern's closest challengers but this season they sit seven points outside the top four despite having prolific striker Erling Haaland in their ranks.
"In the Bundesliga I wish that Dortmund or RB Leipzig could at least compete with FC Bayern in the medium term," City star Gundogan said to Funke Media Group.
"Should Bayern continue to set themselves apart from the competition even further in the next few years, then we can assume that the league will unfortunately become less appealing and interesting to the international audience."
Gundogan and City are cruising to the Premier League title in England, but he feels the competition has a clear advantage on Germany.
He added: "I think that here in England we have more quality in the league.
"Not only at the top, but above all in the middle of the table for teams that don't play in Europe.
"The top teams have also been playing with the best coaches in the world for a long time."
City go into the last-eight tie as favourites, having won 10 of their last 11 Champions League matches against German opposition (D1).
But City have lost four of their five matches at the quarter-final stage of the Champions League under Pep Guardiola, going out at this stage in each of the previous three seasons.
And despite their domestic struggles, Dortmund have gone unbeaten in their past seven Champions League games (W5 D2).
It is their longest streak without defeat in the competition since a run between 2012 and 2013, when they went 11 games without defeat under Jurgen Klopp.
Haaland has 21 Bundesliga goals this season and has also netted in each of his last six Champions League appearances.
Should he find the net in this game, he will become just the fifth player in the competition's history to score in seven straight matches.