The pair face off at the Emirates on Sunday (4pm), with Chelsea looking to take another giant step towards the title.
However, the Gunners may have to make do without their giant German defender.
According to the Daily Mail, Mertesacker escaped serious ankle ligament damage after sustaining the injury in the second half of his side's FA Cup semi-final win against Reading last Saturday.
But subsequent scan results highlighted that he has a sprain.
It is thought Mertesacker will be replaced at centre-half by Gabriel.
Chelsea hold a 10-point lead at the top of the Premier League table.