Plimpton has done it again. Which is the problem with "Mad Ducks and Bears"

George Plimpton's new book is called Mad Ducks and Bears (Random House, $7.95), but it could as easily have been titled Son of Paper Lion. It has a lot of entertaining stuff in it, but—as often happens when a writer revisits terrain he has successfully explored—it fails to match the original.

The book is not at all what it started out to be. In the middle of the 1970 season John Gordy, the Detroit offensive guard, suggested that he, Plimpton and Alex Karras collaborate on a "manual" of offensive and defensive line play. It was to be nothing elaborate: a modest inside look at the game.

Well, like Topsy, it just grew, and now we have a 421-page volume that is not one book but two. The first part is a portrait of Karras and Gordy, painted largely in their own words, and the second is a journal of Plimpton's 1971 training camp experience with the Baltimore Colts when he took a second stab at playing quarterback. Both sections have their merits, but on the whole the first is better than the second. This has less to do with Plimpton's journalistic skills, which are beyond dispute, than with Karras (the "mad duck" of the title) and Gordy ("the bear"). They are, as readers of Paper Lion will recall, men of intelligence and humor, and both qualities are much in evidence here.

We have Karras rambling on about his college days at Iowa, reminiscing about the hazing he got as a rookie from Bobby Layne, and Gordy describing his role in the NFL Players Association (to say nothing of the pair's recollections of a business venture about which the less said here the better). It is funny, interesting talk, and Plimpton has had the discretion to let Karras and Gordy occupy center stage.

In the second part of the book Plimpton himself takes over. The justification for including his account of his days with the Colts is that Gordy served as technical adviser for the television show filmed while Plimpton was in camp, and Karras played across the line in the show's climactic scrimmage. But in the context of a book about linemen, a rehash of Plimpton's Paper Lion experience seems more gratuitous than relevant.

It does, however, give Plimpton the opportunity to explore, briefly, what happened to an exuberant fan who ran onto the field during a Colt game and got coldcocked by Mike Curtis. It turns out to be a rather poignant story: In addition to being hurt physically the poor fellow found his life consequently pretty well messed up, and now wishes the whole thing had never happened.

Such episodes make Mad Ducks and Bears diverting reading, but Paper Lion is still Plimpton's best book. You really can't go home again, George.