Arsenal are still reeling following their unexpected 2-1 defeat to Watford at Emirates Stadium.
A win against the Hornets would have reduced the gap between the Gunners and leaders Chelsea to six points.
However, as things stand, the Gunners are nine points behind the leaders ahead of their trip to Stamford Bridge on Saturday.
The North London side are severely depleted in the midfield due to a mix of injuries and suspensions, and now they have lost midfielder Aaron Ramsey for three weeks with a calf strain. The North London side are already without the likes of Santi Cazorla, Granit Xhaka and Mohamed Elneny.
The Welsh midfielder picked up his injury in the first half of the game against Watford on Tuesday night.
Today, in his press conference ahead of Chelsea game, manager Arsene Wenger confirmed that Ramsey is expected to be out for up to 21 days.
He said: “Well, overall from the other night I think we lose Ramsey, and Giroud has a test. Giroud should be alright.”
When asked about the duration of Ramsey’s absence, Wenger added: “I would say 21 days.”
Alex Oxlade-Chamberlain is expected to partner Francis Coquelin in the Gunners’ midfield on Saturday.