When shooting sports I regularly have some incorrect exposed shots. Usually they are overexposed rather than underexposed. I thought it might be due to sticky aperture blades but after some testing I couldn't find any faults there.
Could it be that in some shots the camera simply doesn't get enough time to calculate and set the correct exposure?
I'm using the camera in A (aperture priority) mode with auto-iso selection on a Nikon D7100 and 70-200 f2.8 VRII lens, and centered weighed metering.
Is manual exposure to be preferred for sports?
Here is an example: