While Wojciech Szczesny has been in excellent form this year—the Manchester City game aside—and signed a new contract in November, Iker Casillas would give Arsenal a stronger presence between the sticks.
The Real Madrid goalkeeper has been sidelined by new boss Carlo Ancelotti, continuing the benching that was implemented by Jose Mourinho last season.
In a year when players are looking to boost their profile ahead of the World Cup in 2014, Casillas will be hoping to beat out Victor Valdes and Diego Lopez. The only way he can do that is with regular first-team football.
It would be unfair for Szczesny to lose his place in the Arsenal side on the back of the best season of his career, but Casillas remains the better 'keeper and would undoubtedly help the Gunners push towards the Premier League title.
According to Spanish online publication El Confidencial, Arsene Wenger is preparing to make a bid that would bring both Casillas and striker Alvaro Morata to the Emirates. This would be of benefit to both sides, especially in light of a recent report by John Cross at The Mirror that linked Lukasz Fabianski with Schalke.
The other side linked with Casillas is Manchester City, which is understandable given their current goalkeeping carousel. However, if the Fabianski move goes through, a choice will need to be made in north London.
Casillas would ultimately give Arsenal the consistent leadership and reliability they have been lacking in goal. Even the recent emergence of Szczesny doesn't guarantee anything in the long term, and at 23 he would benefit from the influence of Casillas while remaining in position to succeed him.
Of course, this all depends on Casillas' willingness to leave Real Madrid, the club at which he has enjoyed huge success and remains a fan favourite.
According to Sky Sports (via the El Hormiguero TV show), the shot-stopper isn't considering a move away from the Bernabeu:
In the future I see myself out of Real Madrid, inside ten years. At 38 it will be much more difficult for me. Today, I'm one of Los Blancos. I'm delighted to be at Real Madrid. In five or six years, we'll see.
While that appears to decide the matter, the lure of first-team football ahead of the World Cup could sway his decision. In October, he appeared to hint at a January exit, as relayed by The Independent:
I have decided I want to be part of this squad for a long time but if the situation doesn't change in three months and you ask me the same question perhaps I will answer that I am planning to leave.
Plus, as we saw with Mesut Ozil, a player stating he will stay with his current club often doesn't make a difference.
Casillas already finds himself on the bench, and January could see him move further from Ancelotti's mind. Arsenal should make the move and give themselves the best possible chance of claiming back the Premier League title.