I suppose it depends on how seriously Southampton treat the game and the chance to get within one round of a Wembley final. I would be pretty sure Arsene Wenger will try his best to change every player who started against Bournemouth on Sunday as he will want his strongest team possible to play West Ham at the weekend. If at all possible he will make 11 changes, but he might not be able to do so given the current injuries.
Certainly he can change all of the starting back four and goalkeeper with Emiliano Martinez, Kieran Gibbs, Karl Jenkinson, Gabriel Paulista and Rob Holding all available. In midfield we could see Francis Coquelin, Aaron Ramsey and Alex Iwobi come in while Jeff Reine Adelaide and Lucas Perez could start in the attacking trio. I wouldn't be surprised to see Alex Oxlade-Chamberlain play even if he did start on Sunday as I still think he needs as much game time as possible.
I'm not sure if Lucas is fit enough to play as he is only just back from the knock he picked up in the last round. With Chuba Akpom injured too I wonder if Yaya Sanogo is still alive and if so could we be privileged enough to get a rare sighting of him. He's a player who has promised so much but seldom delivered due to injuries and just maybe he might get a chance to shine.
Southampton might have the Europa League and their Premier League position to worry about, but I doubt if they will turn their noses up at a chance of making the semi finals. If they play their strongest team tonight they will have to be the favourites to progress and I have a feeling they will play a strong team. That doesn't mean Arsenal aren't in with a chance of winning, but it will certainly make the task a lot tougher.
It's always good to see the youngsters and fringe players get a run and a quarter final exit would be far from a disgrace. I still think they're in with a chance though even against a strong Southampton team and there is still a possibility of a two legged semi final in January to fit in. Once the players come through unscathed I'll be happy and a win would be a nice added bonus too.