Mark Ogden discusses Arsenal's new signing from Dortmund and looks at what Mesut Ozil's new three-and-a-half year contract means for the Gunners. (1:31)

Former Arsenal midfielder Alex Song is training with the Gunners again as he looks for a new club.

Song, who also played for Barcelona and West Ham, was recently released by Russian club Rubin Kazan and is apparently working out at Arsenal in order to maintain his fitness.

The former Cameroon international posted a photo of himself on social media wearing an Arsenal training kit, with the caption "No pain no gain."

Alex Song has been released by Rubin Kazan and is training with Arsenal while he looks for a new club... pic.twitter.com/PBJ0KujRdH — ArsenalFanTV (@ArsenalFanTV) January 31, 2018

He also attended Arsenal's recent home game against Chelsea in the Carabao Cup semifinals, with Jack Wilshere posting a photo of the duo together after the match.

Song joined Arsenal in 2006 and became a regular starter in 2008-09, establishing himself as an integral part of the Gunners' midfield alongside Cesc Fabregas.

But a year after Fabregas returned to Barcelona, Song joined him at the Catalan club in 2012. He returned to the Premier League two years later on loan at West Ham, before joining Rubin Kazan in 2016.

Arsenal currently have a shortage of defensive midfielders after Francis Coquelin was sold to Valencia this month, although it's unclear whether Arsene Wenger has any plans of offering Song a contract. However, Wenger did re-sign Mathieu Flamini on a free transfer after the Frenchman impressed in training following his release from AC Milan in 2013.