"I find that absolutely embarrassing": Jonathan Burkardt faces heavy criticism after the row involving Eintracht Frankfurt manager Albert Riera

"The fact that Burkardt informed his agent and asked him to sort it out – I find that absolutely mortifying," said Franz, who played for Frankfurt himself from 2009 to 2011, on Sunday's Sport1 Doppelpass programme. The 44-year-old then explained his irritation by recalling an anecdote from his early days as a professional at VfL Wolfsburg.

During the 2002/03 season, as former Bayern star Stefan Effenberg was finishing his career at Wolfsburg, assistant coach Bernd Storck approached him about his weight on head coach Jürgen Röber's instructions.

"There was some tension, but then Effe replied, 'That's my fighting weight; I won the Champions League with it (in 2001 with Bayern, ed.).' That's how Effe handled it; this is something completely different," Franz concluded.

Meanwhile, the row with Burkardt dominated Riera's memorable press conference on Friday. The media reports about the row were "total bullshit", the Eintracht manager railed. "What am I supposed to explain? You write whatever you want anyway." The incident happened two weeks ago; when pressed further, Riera snapped: "Get your facts straight. If you're not 100 per cent sure, don't write it."

According to reports, Riera has strained relationships not only with Burkardt but also with Ritsu Doan, Can Uzun and Mario Götze. Such combative public appearances are fuelling growing criticism of the Spaniard.

"At first I thought: Cool, a manager who doesn't mince his words and says what he thinks. But now it's somehow a bit too much; he comes across as very thin-skinned and almost a bit overwhelmed," said Franz, though he still wanted to "defend him" in the Burkardt affair for reasons he had already explained.

Riera only replaced the sacked Dino Toppmöller in early February, and it is unclear whether he will stay beyond the summer. After Saturday's 1-2 home loss to Hamburg, sporting director Krösche stopped short of giving the Spaniard a vote of confidence, leaving Frankfurt's European hopes in limbo.