Off-leash use is not allowed on sports fields because of the safety issues resulting from damage caused by dogs. Holes dug by dogs and turf damage caused by dogs has resulted in many serious twisted ankles and other injuries. Dog feces are also a big problem for sports groups. At some sites, practice can only begin after coaches and parents spend significant time removing dog poop from the field. They must do this because serious infections can result when dog feces come in contact with an open wound: young soccer players fall down and scrape knees all the time. So while those big open sports fields look like perfect off-leash areas, there are good reasons why the use is not allowed.