Arsenal manager Arsene Wenger told "Sky Sports" in a pre-match interview that while midfielder Granit Xhaka has returned from suspension, he has concerns over his discipline heading into the Spurs match this weekend.
"I'm a bit concerned yes because the discipline is important," he said. "We want to be effective in all positions we face. In derbies it is important to maintain discipline.
"He's quite normally a composed and calm guy - sometimes he has a reaction that is a bit impulsive. He has to work on that and keep control of his reactions in the game."
The summer arrival was sent off against Swansea City for a bad tackle that earned him a three-match ban, which came to an end prior to this weekend in the North London derby.
The boss will just need to give him a slap.