The standard answer most time this is asked is don't assume everything was done for a reason, the camera may have already been set to ISO 800 and the photographer might not have had time to change it.
However, this image looks like bright daylight and so ISO 800 seems way off, but in this case the image brightness is a bit misleading, 1/500s f/2.8 ISO 800 corresponds to an ISO 100 exposure value (EV) of 9 - about the same you get a night time sports venues! This was likely shot very early in the morning, or late at night.
Looking at the other settings we note:
- 1.3x crop camera was used
- focal length was 135mm
Applying the standard 1/focal-length rule for shutter speed and accounting for the crop factor would recommend shooting at 1/175. I prefer a 100% margin for safety when dealing with camera shake (resolution has grown massively since the rule was popularized) which would give you 1/350s, not far off what the photographer used.
So given the image was shot in fairly low light it looks like the settings were about right for those conditions (not taking into account image stabilisation if available).