[Sans-Culotte]

I always wondered why McGavin was not credited in The Natural.

I wonder if that is what happened with Arthur Hill as the doctor in A Bridge Too Far who refuses to look at James Caan's wounded Captain (one of the best sequences in the movie, but Hill was not credited)?

[Phsstpok]

I understand it's fairly common for the really good actors (not stars, ACTORS) to do this kind of thing when they see a good part that they want to do for the chance to turn in a great performance, not worry about "carrying the picture."

Robert Duvall also did his part of Max Mercy in The Natural without credit (though IMDB lists the part as "Scotty Carson" for some reason). 

The cast also had great performances from the listed stars, Robert Redford (Roy Hobbs), Glenn Close (Iris Gaines), Kim Basinger (Memo Paris), Wilford Brimley (Pop Fisher), Barbara Hershey (Harriet Bird), Robert Prosky (The Judge), Richard Farnsworth (Red Blow) Michael Madsen (Bartholomew 'Bump' Bailey).

I consider The Natural a perfect movie.  Perfectly cast, directed, written, edited, etc.  Even (especially) Randy Newman's score was perfect. It is timeless and should be watched by everyone.