Pafko at the Wall

http://perival.com/delillo/underworld_triumph.html

This link gives some insight to what the author was attempting to do with this story. There are also links to other articles on the text.

https://depaul.digication.com/discover_chicago_chicago_cubs1/Pafko_at_the_Wall_Response

More critical analysis of the text.

http://genius.com/Stephen-pringle-when-sport-and-literature-collide-annotated

This is from a blog and I tend to be negative on blogs as an outside source but there are some good points here.