Arsenal pair Ignasi Miquel and Johan Djourou should be defending better despite currently playing out of position for Arsene Wenger's side, according to Jamie Redknapp.

The aforementioned Arsenal stars, who are centre-backs by trade, have had to occupy the fullback positions in the continued absence of Kieran Gibbs, Andre Santos and Bacary Sagna and at times they have been ruefully exposed, most recently against Swansea City at the Liberty Stadium.

Although Jamie Redknapp has a certain amount of sympathy for the young Spaniard and his Swiss teammate, he believes they must defend better if Arsenal are to successfully negotiate their current injury problems.

Looking ahead to Arsenal's Premier League encounter against the defending champions Manchester United, the Sky Sports pundit believes Arsene Wenger has a few key decision to make in order to address their problems in defence.

"Thomas Vermaelen has been a huge loss for them (Arsenal) at centre-back and they've really struggled with the amount of injuries they've had in both full-back positions." The former Liverpool and Tottenham midfielder told Sky Sports.

"They've had to fill the gaps by playing centre-backs in those positions like Ignasi Miquel and Johan Djourou, which isn't ideal."

Although Redknapp acknowledges the Arsenal pair are playing in unfamiliar roles, he suggests that can not be used as an excuse, citing the Liverpool side of 2001 as an example.

"But it's still no excuse for how poorly they've been defending, especially away from home. " Redknapp continued while commenting on Arsenal's defensive malaise. "Liverpool won four trophies back in 2001, including the FA Cup and the UEFA Cup, playing with four centre-backs.

"Jamie Carragher and Markus Babbel played left and right-back respectively that season, so I can understand if Djourou and Miquel were a bit lacking going forward, but they certainly should be defending better.

"And when you're a team like Arsenal and you've conceded more goals away from home than any other team, well that tells you everything you need to know."

Arsenal's defensive linchpin Thomas Vermaelen is set to make his return to Arsene Wenger's side barring any late setbacks, and Redknapp intimates the Belgians return could be key for the Gunners.

"There's a chance that Vermaelen will be back for Sunday, which will be a huge boost. The only question is will Arsene Wenger play him at left-back or at centre-back?" He continued. "There's obviously an argument for both, but personally I'd stick him back at centre-back in place of Per Mertesacker.

"Arsenal look a different team when Vermaelen's at the heart of defence, while Mertesacker has really struggled to find his feet in the Premier League. He looks really uncomfortable and his movement just doesn't look right to me."

While concerned with Per Mertesacker's Premier League suitability, Redknapp believes Miquel's problems are being exasperated by a lack of experience and suggests the Arsenal starlet should probably be taken out of the firing line.

Redknapp added: "The problem Arsene Wenger has is that Miquel has struggled as well.

"He's a young lad and I hope he turns into a good player, but at the moment he looks a bit lightweight. Premier League football is hard enough when you're playing in natural position, but he's overexposed at the moment and I'm sure Sir Alex Ferguson will be looking at that."

Arsenal host Manchester United at the Emirates on Sunday looking to banish the memories of their chastening encounter at Old Trafford in August. The Red Devils humbled Arsenal 8-2 but the Gunners' subsequent revival has defied their patently premature doubters who suggested a top four finish was out of reach.