Grease On Front Wheel - Bearings?

[neils]

Hi,

 

I was washing the car at the weekend and found grease all over the outside of the passenger side front wheel. Didn't get a chance to look further due to the weather but assumed it would be a burst CV boot. Finally had a look and the boot is perfect and there is no grease on the inside of the wheel or anywhere else, just the outside face. Couldn't think where else it could have come from so popped the centre cap off, not sure if it's any more greasy than normal but I noticed marks around the centre bolt. There's slightly polished clean bits as can be seen in the photo as if there's been movement. I can't feel any movement, the bolt is tight and can't think of any reason that would have been a tool used on it recently. Should I be worried?

 

Any advice much appreciated.

 

Cheers...