Chamberlain limped out of Arsenal's 2-1 FA Cup win over Man United with a hamstring problem
However, initial thoughts were that he could face three or four weeks on the sidelines - something scans are expected to confirm once the initial swelling has gone down.
The clock is ticking loudly with Roy Hodgson set to name his squad a week today for the European Championships qualifier against Lithuania on March 27 and the friendly against Italy in Turin four days later.
Manager Arsene Wenger said: "Chamberlain has a hamstring strain. The only thing we don't know is how bad it is, because usually the scans are only done 48 hours after the accident."
The injury is the latest in a long line of soft-tissue problems to hit Arsenal players this season, a situation that has caused Wenger to re-think his approach with a thorough overhaul of the medical department at the club, with a position as their new soft-tissue specialist already being advertised.