Mikel Arteta has been great this season. Ever since his move to the club on the August transfer deadline of 2011, the Spaniard has been a fantastic servant to the club.
Having said that, he is not a defensive midfielder.
Arteta has filled in admirably, but it is time that Wenger signed a proper shield for the back four.
The departure of Alex Song to Barcelona meant that Wenger has had to choose between Arteta, Emmanuel Frimpong (who was loaned and injured), Francis Coquelin (talented but inexperienced) and Jack Wilshere (best option but needed in a more advanced roll).
If Wenger does manage to bring in a top defensive midfielder, Arteta will be able to attack more. This frees up the Spaniard to team up with Santi Cazorla and Wilshere in more advanced roles.
Lukas Podolski, Olivier Giroud and Theo Walcott would all benefit from this as they'd be getting a higher quality of service.
The back four would also benefit because of the improved shielding they would enjoy.
While Arteta has done the best he is capable of, it is time for Wenger to bring in a proper defensive midfielder.