England head coach Stuart Lancaster calls in back-up as injury list starts to grow ahead of Six Nations Gloucester fly-half Freddie Burns, who delivered an impressive cameo in England's record victory over New Zealand last month also requires a scan on a knee injury he sustained in his club's win over Mont-de-Marsan in the Amlin Challenge Cup. Burns suffered suspected medial ligament damage to his left knee when he was tackled in build up to Jonny May's opening try in the ninth minute. He had treatment but came off after 12 minutes. "He will have a scan but it looks like a medial knee ligament," said Nigel Davies, Gloucester's director of rugby. We could see that he was struggling. He wanted to stay on but we didn't think it was appropriate that he did if there was an injury so we brought him off. It's something that he has had before. He had it in pre-season and it took him two to three weeks to get over that. Hopefully it will be something similar. Northampton flanker Clark is another doubt for the Scotland game, having sustained a shoulder injury in his club's defeat by Glasgow on Saturday. Clark's team-mate Courtney Lawes also sustained a shoulder injury and a bang to his head but is not thought to be a major concern. "Calum certainly has a very sore shoulder," said Northampton director of rugby Jim Mallinder. I think he has done a little bit of damage there. It is his AC [acromioclavicular] joint. He is very sore and his arm is in a sling at the moment. Jamie Gibson of London Irish replaces Kvesic in the Saxons squad for their games against Ireland Wolfhounds in Galway on Friday, Jan 25 and Scotland A at Kingston Park, Newcastle seven days later.