Can't say without the better picture. From your description, though, and from what little I can see in the picture, I'd say a die crack.
heres the close up ! close up from my tv i hope it works if not i have another idea! and thank you for your time!!
Looks like a lamination error by your pics.It's certainly not a die crack they don't have that look to them and this doesn't appear to be a raised line on the field. JC
