By Chris Harris

Arsène Wenger will NOT ask Jack Wilshere to fill Alex Song's boots on Tuesday night.

The Cameroon international has been ruled out of the second leg of Arsenal's Champions League tie with Barcelona after failing to shrug off a knee problem, leaving Wenger with a substantial gap to fill as his team defends a slender 2-1 advantage in the Nou Camp.

Song has emerged as a powerful defensive force in the past two years, curbing his own attacking instincts to offer protection to the back four. Wilshere is arguably the most versatile midfielder at Wenger’s disposal but he is not a candidate to replace Song.

"[That role is suited] more to Diaby or Denilson," said Wenger. "We will not want to keep Wilshere in a purely defensive role. [How to replace Song] is one of the things to sort out."

Denilson started the 0-0 draw with Sunderland on Saturday and was criticised by some sections of the Emirates crowd before he was replaced by Marouane Chamakh with 22 minutes left. Wenger admits the Brazilian was below-par but insists he has much to offer.

"It wasn't one of his best performances but I feel that Deni doesn't get the credit he deserves and he always works hard for the team," said the manager.

"It was difficult for the midfielders on Saturday because they marked us very tight and we only found space in the last 20 minutes. He had given a lot."

Copyright 2014 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source 7 Mar 2011