The 26-year-old Nigerian left Russian club Rubin Kazan during the January transfer window and though he lacks match practice he feels fit again after facing Stoke City on Saturday.
Martins enjoyed a memorable three-year spell at St James' Park and is raring to get his career back on track in the Premier League.
Martins said: "I am happy that I am back in England. My last games were on December 5 and Saturday. My body is aching but I am happy that we have won.
"I am very impressed. Coming here and playing for Birmingham. Everyone is very friendly and I am happy that I am here. I have been welcomed."
It looks like Martins will keep his place in the Birmingham attack and he will lead the line against his former club at St Andrews.
Obafemi Martins Face
Obafemi Martins Face
Obafemi Martins Face
Obafemi Martins Face
Obafemi Martins Face
Obafemi Martins Face
