mustafi was excellent in the first third of the season. in the 12 league games he played from the start of the season until december 10th (when he got hurt, i think), we had a record of 9 wins, 3 draws and 0 losses. he missed a few weeks with an injury, he came back, we won 3 and draw 1, then everything went to shit, starting with the loss to watford.
i thought he was excellent until he got hurt. maybe he never fully recovered his fitness and it just wasnt publicized. he showed great athleticism, aggression and tackling ability before he got hurt. and it was his first season in england without having a preseason with us. i expect he'll be very good next season.
im more worried about kos. right now, he feels like a 1 game a week player. id play him in every league game, i'd rest him in the cup games and the early stages of the europa league. manage his fitness, keep him healthy. if we go with kos-mustafi-monreal in the league (which it looks like we will), then you can use gabriel, holding and mertesacker in the cup/europe games. plenty of depth.