He thinks it might be an underlying issue that he's had from before he joined them. As far as I know, he wasn't ever out with a thigh injury before.
Tetteh hopefully only out for a few weeks, a quick update on the others from HDM... Seri and Ozan will benefit from a week without a game ahead of the visit to Cardiff City and so too, will Dimitrios Pelkas, Harvey Vale, and Xavier Simons, while Dogukan Sinik is expected back in training in the next few days. Greg Docherty continues to progress well following his injury but new signing Salah-Eddine Oulad M'Hand is likely to be sidelined until after the international break later this month. City remain without long-term absentees Vaughn Covil, Brandon Fleming, Allahyar Sayyadmanesh, Josh Emmanuel, James Scott and Adama Traore.
It means they'll benefit from another week training with the team, rather than them actually benefiting from a week with no game.