A different ending in the book
The novel (by Bernard Malamud) book doesn’t mention Roy’s childhood, except he (Roy) admits his mother was a whore, his father died when he was very young and he went to live with his grandmother until she died, then was put in an orphanage. There was no childhood sweetheart who grew up to be Glenn Close. Her part (Iris, the woman in red, not white) was a Chicago fan of his who simply stood to rout for him when he came up to bat that memorable time he broke the clock (and his slump) in her presence. They got together. She was a never-married single mother, 33 years-old (and already a grandmother via an illegitimate daughter). She had no son, by Roy or any other man.
In the end, Roy, still wanting to marry Memo (who was penniless in the book) and fearing his longevity in the game, succombed to the bribe of $35 thousand by the Judge to throw the playoff game. But feeling okay (and he always played left field, not right, as Bump Baily had), he changed his mind in mid-game. However, he struck out (using the alternate bat) in the last inning with the winning run on base instead of getting the big hit as portrayed in the movie. And the Knights lost the pennant.
Roy still got the 35K after the game but felt bad and that’s when he took it back to the Judge, and there in the office he beat him up, Gus too. While there he also discovered that Memo had helped set him up, and she still pined for Bump anyway. And that’s where the author left it, except that Iris had written him a letter and now he knew she was pregnant by him. The end.