Michael Ballack could be back for Chelsea for their blockbuster against Arsenal on December 16.

The Germany midfielder, 31, will step up rehabilitation on his ankle injury in the next week as he nears the end of seven months out.

Ballack had treatment yesterday after successfully coming through 45 minutes of a reserves match against Birmingham on Monday night.

Chelsea's medical staff are also planning to increase the workload on Ballack's ankle, which he damaged in April and which required two operations.

The unbeaten Gunners are top of the Premier League and five points clear of fourth-placed Chelsea.

A Blues source told The Sun: "Avram Grant is desperate for the squad to be at full strength for that one.

"The club's had its fair share of injuries in recent weeks - but this is a massive game."