Ba has talked down its significance.
"Just because you have the No 9 shirt doesn't mean you will score goals. I had No 29 and then nine at Hoffenheim, at West Ham 21. The number does not score goals.
"Maybe it would mean something to the supporters, but you can have the No 9 shirt and never score a goal. I am not going to take it off someone else.
"When you look at the No 9 it is the striker and No 1 is the keeper, No 5 is the central defender, but it is not because you wear No 9 or 19 that you can score some goals.
"That is all down to you and your feet. I am quite happy with the number I have got now."