Wannabe football player?

Late this morning I seen a dark black mark on Daisy's face when he was laying on a hay bale in the hayshed.  I don't know how he got the mark.  Is he trying out to be a football player or some other sport?  

I tried to take a photo of his mark.  But he didn't want to sit still for a photo.  He rubbed against me or would lay and roll around on the ground next to me.  By the time I got some photos the mark was no longer a dark black.