Arsenal manager Arsene Wenger admitted he is concerned by Granit Xhaka's disciplinary record ahead of Sunday's north London derby at home to Tottenham.
The Switzerland midfielder is in line to play against the Gunners' fierce local rivals for the first time, with Santi Cazorla likely to be still sidelined with an Achilles problem.
Xhaka, 24, has picked up eight red cards for club and country since April 2014 and is returning from a domestic ban following his dismissal in last month's 3-2 win over Swansea.
He scored his first Champions League goal as Arsenal came from 2-0 down to beat Ludogorets in Sofia on Tuesday night and progress into the last 16 for the 17th straight season.