The center focus point on DSLR cameras is generally the most precise (at least with f/2.8 or wider max aperture lenses). To use the center AF point in vertically oriented sports photography often means placing that focus point on the player's waist. And this tactic is usually a good one. Unless the player bends forward (towards the camera) significantly as this position places the plane of sharp focus well behind the player's eyes – which usually have to be sharp. In this case, center AF point on the waist worked fine.