Ever since he was induced to unretire by the gleam of an $8 million paynight against Larry Holmes, Muhammad Ali has been jawing about his upcoming place in history. He will become, he boasts, the only heavyweight champion to regain the title four times.

Big deal. If it happens, which is doubtful, it was made possible only because Ali was the only champion ever to lose the title three times. Altogether, the four-time business is one bit of braggery Ali might be wise to drop. It raises questions.

That it will come to pass in Las Vegas on the night of Oct. 2 that Ali will become the champion again is not quite a professional opinion. That city's odds-makers, a notoriously unromantic lot without sentiment for a gallant 38-year-old challenger, have posted Holmes as a solid favorite to keep his title, Ali's vows notwithstanding.

Larry Holmes does not level anybody with a single punch, and in some bouts he has tended to weary in the late rounds. But he has licked everybody he has fought since he turned pro 35 fights ago. He is a busy fighter who has posted eight knockouts in the eight times he has defended his title since winning it from Ken Norton in 1979. He is 31 years old and his physical dimensions are almost a likeness of Ali's, but unmarked by Ali's latter-year flab.

The esteem for Holmes in this fight may be less a solid belief in Holmes than an anti-Ali vote. Time has laid a heavy hand on Ali. He is coming back as a sweated-down 270-pounder who can't point to a single impressive fight in the last five years.

A slow, out-of-shape Ali was fortunate to escape with decisions he didn't deserve against such undistinguished opponents as Jimmy Young and Alfredo Evangelista. When they held up his hand and called him a winner the night he fought Ken Norton, it was the Great Yankee Stadium Holdup after a fight clearly won by Norton. Later for Ali, there was the awful ignominy of a defeat by near-novice Leon Spinks, who took his title before giving it back.

Time, which brings everything to light, showed Ali bereft of the speed of hand and foot that used to be his greatest resource. Relatively, he became a lumbering old war horse, supported mostly by his ring lore, a defensive asset of little help in sustaining a punching attack.

Sadly, the image has suffered. The Ali who for so long was a fascination as the handsome braggart who always made good, who could sometimes call the round, who had the high spirit and skills to deflate the likes of Sonny Liston and George Foreman, who was indulged by his public when he called himself "The Greatest" and amused himself by ad libbing the doggerel he called poems -- that Ali is of a bygone time.

Of too recent memory is that bad scene of a bloated Ali boxing exhibitions.

The big belly is gone now and he's down to 226 pounds and, by fight night, it may be 222.The weight is proper and tells of Ali's determination to get into shape for this one, because he has long hated the training regimen and has looked forward to retirement. But the right weight is no guarantee of the rightness of other resources.

Two months ago, he came out of the Mayo Clinic after a short stay and proclaimed himself fit. But his personal physician of many years until he left the Ali camp, Dr. Ferdie Pacheco, is skeptical. Pacheco, who has begged Ali not to return to boxing, says he would rather hear a report of Ali's fitness from a proper hospital source, rather than from Ali.

Pacheco speaks of how "punishment to an already weakened system accelerates damage to tissues that are already falling apart. And, at 38, it happens faster in Ali's business. Even a younger athlete is diminished by two years absence from the wars." He says he noted in 1977 a growing huskiness in Ali's voice "due to an accumulation of blows to the voice box."

Ali always has the belief he can psych an opponent, as he has often done, and he will try it on Holmes, a former inferior as his longtime sparring partner. If Holmes knows Ali's moves, then the ring-smart Ali knows Holmes' moves better. Ali never did fight much in sparring sessions, anyway, concentrating on defense.

Holmes will be in with an Ali different from the man he worked with before the George Foreman fight in Zaire and the Joe Frazier thriller in Manila. tThe slower Ali can be hit with a jab now, even as Leon Spinks demonstrated, and that happens to be what Holmes does best. Holmes' camp is already telling him to establish that good, repetitive jab and then work off it against the no longer sprightly Ali.

His several attempts to retire bespeak Ali's loss of interest in fighting for a living. Although he has made millions, he has never been the saving type; has always commanded a potentate's retinue. Ali, in retirement, began missing those whopping paychecks in the millions. So he's fighting again, and it could be profitable only in the dollar department.