Leandro Trossard will undergo further tests after sustaining a calf problem during Arsenal's Champions League win over Bayern Munich. The Belgian attacker was forced off after 38 minutes at the Emirates, having recently scored against Tottenham and Sunderland.
Arsenal's medical staff are assessing the extent of the injury, with fears he could be sidelined for several weeks. Manager Mikel Arteta said: "With Leo, we don't know. He said he felt something. We didn't want to take any risks, obviously."
Meanwhile, Viktor Gyokeres and Kai Havertz had scans on Wednesday as Arteta remains hopeful they could feature in Sunday's Premier League trip to Chelsea. Gyokeres has been absent since being substituted against Burnley, while Havertz has yet to appear this season following surgery.
Gabriel Magalhaes also had a further scan to clarify his recovery from an issue sustained on international duty. Initial tests suggested the Brazilian defender could miss at least four weeks. Arteta expressed confidence in coping without him, recalling last season when the team managed for three months without the centre-back.
Arsenal travel to Stamford Bridge holding a six-point advantage over their London rivals. They are unbeaten in seven league meetings with Chelsea, though both draws in that run have come at Stamford Bridge.
