The Gunners must face Tottenham in a gigantic clash at Wembley stadium, which sees the fifth and sixth placed teams in the country face each other.
Both sides want to get into the top four, and Spurs are a lot closer at the moment.
Arsenal know their only realistic chance of the top four is to win most of their games. And losing to a rival for that position, or even getting a draw, is not good enough.
It seems they will have to do without Cech, who is suffering from a calf injury, with David Ospina set to replace him in goal for the clash.