Former Liverpool star Dietmar Hamann believes Philippe Coutinho should be dropped by Bayern Munich in favour of Thomas Muller.
Coutinho joined the German champions on loan from Barcelona in January after a difficult 18 months at the Nou Camp.
The Brazilian has managed two goals in his first 10 outings for Bayern and played in the Champions League win over Olympiacos this week.
However, some of his recent performances have failed to impress and manager Niko Kovac was the former Liverpool man after the 3-2 win on Tuesday.
Coutinho and Muller were both part of the starting XI in Greece, but with at least one of the pair expected to drop out against Union Berlin on Saturday, Hamann believes it's the Brazilian who should make way.
"There is a difference between not playing well and playing badly," wrote Hamann in his column for Sky Sports Germany . "Coutinho is playing badly at the moment.
"He is on loan for a year, has already played a few games for Bayern and I can't see any improvement in his performance at all.
"That's why I would let Muller play against Union Berlin at the weekend, centrally behind Lewandowski. With Coman and Gnabry on the outside.
Coutinho's arrival has seen Muller's opportunities increasingly limited at the Allianz Arena.
The 2014 World Cup winner has started just three of Bayern's eight Bundesliga fixtures this season and is understood to be growing frustrated by his lack of game-time.
His current situation has also led to reports in Germany that the 30-year-old could look to leave the club in January, with Manchester United and Inter Milan among those thought to be interested.
And Hamann, who started his career with Bayern, thinks his former club would be making a big mistake in allowing the forward to leave.
He added: "I am reluctant to participate in such speculation. But one thing is clear to me: allowing Thomas Muller to leave in the winter would be fatal.
"Firstly, because I find him more valuable to the team at the moment than Coutinho, and secondly because he is the last great identification figure of this team.
"His word carries so much weight in the dressing room that you can't do without it.
"I think he and Manuel Neuer are the ones whose words and leadership this team is building upon."
