About EminSgl/fieldghost
You run an off-the-shelf detector on sports footage and it does fine — right up until a ruck forms, a tackle happens, or two players cross paths. For a few frames, your subject is gone. Most auto-tracking pipelines handle this one of two ways: drop the track (now it's two different "people" before and after the pile-up) or freeze a box on the last known position and call it done (now it's confidently wrong for half a second).