It's been reported on several occasions the Jürgen has issues with his pitch discipline in game and even in practice.
One example.
Jürgen Klopp has addressed Marko Grujic‘s knack for producing late challenges, insisting the Liverpool midfielder needed to avoid being “lazy.”
Grujic was criticised for a strong tackle that left Crystal Palace centre-back James Tomkins injured in May, and then picked up a suspension for two yellow cards at the summer’s European U21 Championship.
Lining up for the Reds this pre-season, the 21-year-old provoked ire from Palace manager Frank de Boer for a lunge at Wilfried Zaha, with the Dutchman saying it was “not appropriate.”
Addressing that challenge and Grujic’s questionable approach off the ball, Klopp agreed that this was a flaw in his game.
“I didn’t see it properly at the time but I heard it could have been a red card,” he told the Liverpool Echo.
“That’s not good. For Marko, it’s something that he has to change.
“He’s a fantastic player, a really skilled boy. Tall, quick, talented footballing wise, all good.
“But in these defensive situations, you always need to be early enough there so you are close enough to make a challenge and not a foul.”
“It’s about coming too late, switching off the machine, trying to sort a situation in which you were late in mind. I hate that.
“When that happens you need to run, not foul. Make more steps, go, go, go. For me it’s always a bit lazy.”
https://www.thisisanfield.com/2017/07/Jürgen-klopp-urges-marko-grujic-curb-lazy-defensive-approach/