By Richard Clarke

Mathieu Flamini has been ruled out for three weeks after picking up an ankle injury against Liverpool on Tuesday.

As a result, Arsène Wenger is likely to bring in Gilberto for the crucial Premier League clash at Old Trafford this Sunday.

The Brazilian replaced Flamini when he was forced off at Anfield before half-time. It was ultimately a disappointing night for Arsenal and now the aim is to recover straight away. In fact it is essential if Arsenal are to keep their season alive. Even Wenger has labelled this weekend's game as must-win if his side are going to come back and take the title.

Robin van Persie, only a substitute in midweek, will be fit to start but Bacary Sagna will be absent due to an ankle problem.

"I believe Mathieu will be out for three weeks," Wenger told Arsenal TV Online on Thursday afternoon. "It is a big blow but Gilberto has a lot of quality and experience. He will come in. He can help the team recover and focus.

"Apart from that we don't have any other injuries from Tuesday. We have a few bumps and bruises but nothing special.

"Robin van Persie is available. He had two good sessions yesterday and today. He looks to be OK and we'll see how we go from here. But Bacary Sagna is out."

Arsenal TV Online subscribers will be about to see the full video interview on Friday morning. In it, Arsène Wenger talks about: the crucial decisions at Anfield, coping with criticism, picking his side up after defeat, the loss of Flamini before half time. why this game is a cup tie, the FA Cup game at Man United earlier this season, the form of Cristiano Ronaldo and envoking the spirit of 1998.

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 Richard Clarke 10 Apr 2008