Merson explained in the Daily Star: "The board are not going to sack him. Why sack a manager who makes a profit in the transfer market every year and gets you into the Champions League every season?
"But I know Arsene. I played for him. He will be hurt by what's happening at his club - and I'm sure it's crossed his mind to walk.
"For me, that would just be another mistake, and it would be hugely unfair of him to do it if they don't make the Champions League again this season.
"He must take responsibility and turn it round, but that means admitting his mistakes and learning from them - and I'm not sure he is very good at that."