Estimate the location of an object in a field using computer vision and math
Your problem is focused on the object detection perspective. For a intro into the topic with some code you could look into this - https://medium.com/analytics-vidhya/detecting-objects-on-ip-camera-video-with-tensorflow-and-opencv-e2c25297a75a.
General object detection is quite easy for the second picture but for the first it would be a bit difficult. You could use dlib and CNN networks such as YOLO and RCNN (family of models).
Yes you could do it with two cameras. The configuration depends on you whether you use selected area for both cameras or both cameras cover the entire field.
https://www.geeksforgeeks.org/detect-an-object-with-opencv-python/ - The code here detects stop signs. You could find a dataset which deals with footballs/sports and do the exact same.
This link provides your objective for close range (zoomed in) photos - https://towardsdatascience.com/yolov2-to-detect-your-own-objects-soccer-ball-using-darkflow-a4f98d5ce5bf