I like what you have captured in the first two photos.
1. The small guy is surrounded with no where to go. The color and crop are good. The prey is snatched.
2. The eyes of the ballcarrier shows the emotion of being chased with the open field in front of him... mob just trying to catch him.
The side show is his blocker coming up on a pursuer...another little guy ready to attack.
thats part of the issue is that i used the quantaray for those shots. im in the process of buying a 70-200 f2.8. that lenses will be more crisp and focus faster. i had some good shots but they came out blurry. i wanna say at 300mm the lowest i saw the aperture is 5.6??? it will be nice to get 2.8 at 200 when standing on the sidelines.