At 21 years old, Serge Aurier would represent a long-term replacement for Sagna.
Aurier has had a breakout season for Toulouse, notching up six goals and six assists in 31 Ligue 1 appearances. While he's primarily a right-back, versatility is one of his strengths as he often plays as more of a right midfielder. He is comfortable in any position across the back four.
The right-back has already been capped by the Ivory Coast seven times, and he is set to play a key role in The Elephants' 2014 World Cup campaign.
Although his lack of experience at the highest level means it could be a risk throwing Aurier straight into the deep end of a grueling Premier League campaign, the Ivorian is physically imposing both in the air and on the ground.
He suits Arsenal's style of play, too, as he's always looking to make forward runs and put crosses into the box.
Aurier has stated, via Foot Mercato (h/t Sky Sports) that he wouldn't be able to refuse a move to Arsenal, and considering his age as well as the fact that he plays in Ligue 1, he seems like a classic Wenger signing.