Borussia Dortmund vs Arsenal: Calum Chambers and Nacho Monreal miss training and could join Mathieu Debuchy on the sidelines

The defenders did not train today

Arsene Wenger has much to think about during training today (REUTERS)

Arsenal's injury list is growing by the game.

First Olivier Giroud broke his tibia in the 2-2 draw at Everton at the end of August, and on Saturday Mathieu Debuchy suffered an ankle injury that could keep him out for two months.

More bad news for Arsene Wenger ahead of tomorrow night's Champions League group stage match at Borussia Dortmund - Debuchy's deputy at right-back, Calum Chambers, missed training today.

Alongside Chambers, the left-back Nacho Monreal also missed training and is a major doubt for the fixture. Kieran Gibbs is expected to come in for Spaniard.

Calum Chambers missed Arsenal training today

Nacho Monreal is also a doubt for Borussia Dortmund

The 19-year-old Chambers has already made seven appearances in all competition for the club this season since his £16m move from Southampton during the summer.