Franck Ribery is a "ticking time bomb," according to former Bundesliga referee Thorsten Kinhofer, after the Bayern Munich winger narrowly avoided being sent off in the 5-0 cup win at CZ Jena on Friday.
Ribery, 33, has already been involved in a number of controversial incidents this season at Bayern.
He narrowly escaped a red card in the German Super Cup when he appeared to elbow Borussia Dortmund right-back Felix Passlack twice.
And in the aftermath of the match, Bayern captain Philipp Lahm revealed that he had warned Ribery over his temperament, but admitted: "I can't guarantee anything."
Ribery was also strongly criticised earlier in the summer by his new coach Carlo Ancelotti for shoving Inter Milan's Felipe Melo during an International Champions Cup game.
And Ribery was involved in a controversial incident once again on Friday when the Bayern winger hit Jena defender Matthias Kuhne's head while fighting for the ball.
However, the former France international was not booked, and was later defended by his opponent.
"You should not overrate it -- I do believe that he used his elbow, but it was all within the limits, and thus not an unfair situation," Kuhne said, although he added: "Still, it'll be interesting to see how he'll be perceived by the Bundesliga refs this season."
Speaking to Bild, one former referee, Thorsten Kinhofer, has warned Ribery that he will be closely monitored this season.
"Franck Ribery is a ticking time bomb," Kinhofer said. "Sure, he gets fouled a lot, but he is also easily irritated. The opponents try to make use of that by provoking him. It can also be tactics.
"The question is whether he's willing to learn at his age. You also have to make the club discharge its duties to appeal to him."
Elsewhere, Mats Hummels was delighted to score his first Bayern goal as he sealed the 5-0 cup win with a 77th minute header.
"Scoring goals is the most beautiful thing in football, even for defenders," Hummels said.