Mathieu Flamini Injury Is Major Arsenal Blow for Borussia Dortmund Tie

Understandably, the focus of attention for Arsenal during the transfer window was the completion of the club-record deal to bring Mesut Ozil to the Emirates Stadium from Real Madrid.

The £42.5 million shelled out for the Germany international has already been deemed money well-spent with the Gunners topping the Premier League and players such as Aaron Ramsey feeding off the cool confidence of their new teammate.

But, arguably, one other Arsenal signing during the summer has been just as successful as Ozil. Step forward, Mathieu Flamini.

However, the Frenchman has now been ruled out of the Champions League tie against Borussia Dortmund due to the five-day ruling on concussion after Flamini suffered a head injury during Saturday's league win over Norwich City, as manager Arsene Wenger confirmed on the official club website Arsenal.com:

"

He has practised normally but we will not play him because there is a five-day rule that we will respect.

We will not to take any chances. It was a concussion and the doctor advised us not to play him.

He will be OK for the weekend.

"

Wenger could now turn to Mikel Arteta to step in for Flamini against Jurgen Klopp's team at the Emirates on Tuesday.

The former Everton man has the attributes to fill the defensive midfielder role, while Wenger could also bring in Thomas Vermaelen as a potential replacement.

Flamini had been released by AC Milan at the end of last season following a five-year stint in Serie A with the San Siro giants.

Prior to that spell in Italy, Flamini had played for Arsenal between 2004 and 2008. And it was to the Gunners boss he again turned to during the summer, as he trained with the North London club during preseason. Wenger saw enough in that period to recognise the value of adding Flamini to his squad for the current Premier League campaign, and both club and player agreed a two-year contract.

The 29-year-old midfielder has enjoyed a resurgence in his own career as well as helping to rejuvenate Arsenal this season.

While Ozil has been pulling the strings for Wenger alongside Ramsey, Flamini has been a bedrock in front of the Gunners' back line this season.

According to Squawka.com, Flamini has recorded a passing accuracy of 93 percent, while Ozil has an average of 87 percent.

Flamini will join Theo Walcott, Lukas Podolski, Alex Oxlade-Chamberlain, Abou Diaby and Yaya Sanogo on the sidelines, but the Gunners have not felt the loss of those players much in recent weeks.

The situation could be different with the absence of Flamini, even just for one game.