70-300 L IS does soccer

It was overcast, and I wanted the shutter speed above 1/2000th, so I used auto ISO--anathema to some of the posters here, I realize, but don't understand, since LR noise reduction handles noise so well. Don't quite understand the sharpness criticism, I must admit; brighter light produced sharper images, but this doesn't seem that soft to me. Oh well.