Per Mertesacker looks set to be ruled out of Arsenal ’ s derby against Chelsea although the defender has escaped any serious ankle ligament damage . Mertesacker , captain during the long absence of Mikel Arteta , limped off during the second half of the FA Cup semi-final against Reading at Wembley on Saturday . There were fears of a serious injury for the 6ft 6in German after he twisted the joint but subsequent scans have shown it is a minor sprain . Per Mertesacker will miss Arsenal 's visit by Chelsea on Sunday due to an ankle injury . The stand-in Gunners captain went down in Arsenal 's FA Cup semi-final win over Reading on Saturday . He is not expected to be fit in time for Sunday , however , and likely to be replaced at centre-half by Gabriel Paulista , who has started three times in the Barclays Premier League since he was signed in January from Villarreal . Chelsea come into the match with a 10-point lead over their London rivals and will need to capitulate in spectacular fashion to not take the Premier League title . Second-placed Arsenal , on 66 points , lead Manchester United on 65 and Manchester City on 64 . Scans showed the 6ft 6in German had just a minor ankle sprain when a more serious injury was feared . Mertesacker was substituted around the hour mark by Gabriel Paulista , who will deputise for him on Sunday .
Per Mertesacker twisted his ankle in FA Cup semi-final at Wembley . Scans revealed the stand-in Arsenal captain escaped serious injury . Arsenal beat Reading 2-1 after extra-time in Saturday 's match . They host Premier League leaders Chelsea on Sunday at 4pm . CLICK HERE for all the latest Arsenal news .