George Boyd out for Scotland as Craig Bryson, Chris Burke, Kevin Thomson and Lee Wallace are called up McGhee explained the thinking behind the inclusion of Thomson, who has not featured for the national team since a friendly against Sweden in 2010. He said: "We felt that we needed numbers apart from anything else. We are looking at having quite a few players on one yellow card on Friday night so we could go into the Macedonia game with any of them missing through suspension, where any of them to get a yellow card. We had to have some cover and we felt we needed the quality of players like Kevin. We know the boy well, we know the quality he has. Although he's not played a lot of games in the last couple of years and he has been hampered through injury, he is playing again and Gordon knows him well enough to trust that not only can he come here and help us maintain the level in training, but be ready to be asked to step in at some stage and do a job at least for part of the game. Also called into the squad is left-back Lee Wallace, who is plying his trade with Rangers in the Scottish third tier. McGhee added: "Everyone tells us he's the best player at that level in the league. We know he's a trustworthy lad, we know the type he is and we know we can call him in and he will come with enthusiasm. Again, he will keep the level of training where it has to be and, if he's asked to play, he will do a job.