Stan Papi came off the disabled list today and rejoined the Boston Red Sox after Knee surgery.

Root for him.

Before it's over, the versatile Papi, an infield insurance policy the Sox got in trade for pitcher Bill Lee, is going to be in a pennant race this season.

Root hard.

Papi has made it back from the edge of suicide, from what doctors mistakenly told him was insanity. He has overcome a season in hell.

Knee surgery, the normal athlete's idea of utter despair, hardly touches Papi at all.

"I'll beat it," he says. "I'll never worry . . . never again . . . not after '75 . . .

"The idea of suicide was sweet to me then," continued the boyish, exuberant 28-year-old, thinking back to the lost year when he thought he was mad. "I didn't care whether I lived or died.

"When the doctors said, 'These electric shock treatments could kill you,' I said, 'Oh, yeah? So what?'

"During those four months in that mental hospital, the psychiatrists had me convinced that I was totally crazy, They had me hating my dad, hating everybody.

"It never crossed my mind that so many doctors could be wrong, that the symptoms of low blood sugar-hypoglycemia, which is what I had-sometimes mimic those of a severe mental breakdown.

"I still have the scars on my temple from the shock treatments-seven times they did it.

"They give you a muscle relaxer and a rubber mouthpiece so you don't snap your bones and break your teeth when the jolt hits you.

"I still remember the headaches afterward. But that's about all I remember. My memory for '73 and '74 is mostly gone. When I meet guys I played with in the minors, I can't remember their names.

"In fact, my memory is not too good on anything. Math is a problem for me. I'm not as quick as I once was."

Papi gives his characteristic self-deprecating laugh and screws up his expressive, handsome face to show how he has to furrow his brow in thought to figure out his batting average.

"Sometimes I still ask myself, 'Why me? Why'd it happen to me?' You wouldn't believe the looks I get when people hear I've been in a mental hospital. They just don't want to talk to me.

"I tell them, 'I wasn't crazy. I had a disease-hypoglycemia.' But they just don't want to look you in the eye.

"Despite everything, I actually think it made me a better person. It certainly made me more determined to prove that nothing was wrong with me and to make the majors."

Since missing a season and a half, Papi has returned to the game a better player-one surrounded by affection.

After being AAA shortstop of the year at Dever in '77 he played all of '78 with the Montreal Expos as a utility man.

When Papi was traded to Boston, Montreal General Manager Charlie Fox gave a Bosox official a lucky penny, saying, "Keep this for Papi. That kid's going to help you a lot.He's got 'Winner' written on him now."

One would expect Papi to be adopted by the Red Sox fans. Instead, he has been booed in batting practice before ever playing in a Boston game and is the butt of jokes on talk shows.

Fans think it amusing-poetic justice-that the player the Sox got for the outspoken cult-figure Lee should tear cartilage hustling to first base on the first play of the first spring training game.

"I'm just the guy who was traded for Spaceman Lee, that's all the fans know," says Papi. "He was popular and famous.I'm kind of a nobody. I'll never be the character that he was. But that doesn't mean I'm not just as good a player."

The irony in all Papi's woes is that they have left him open and gregarious, rather than withdrawn. Fielding grounders makes him happy as a kid.

Once diagnosed, Papi cured his hypoglycemia with medication and diet. His acute suicidal depression disappeared.

Not surprisingly, Papi has helped exocrise his memories by facing them-talking freely about his past and visiting patients in mental institutions with similar symptoms.

"Every day I get letters from people who have heard about my case, saying, 'Please send information about hypoglycemia. Someone in my family has the same symptoms,'" says Papi.

Papi always answers, and sometimes visits. "I tell them all the same thing: it's simple," he says. "Get a full five or six-hour glucose tolerance test . . . not the two- or three-hour test that some doctors say is enough. Mine didn't show up on the shorter test.

"I believe I've helped turn several people around."

Often, however, Papi meets severe medical opposition. "I'll speak at a banquet and doctors will stand up and fight me tooth and nail," says Papi. "I tell them, 'All I know is what happened to me.'

"Books have been written claiming that large numbers of people in mental institutions are really hypoglycemic."

It would be hard to touch a more complex or moot medical issue, one tangled by semantics and theory of the brian.

A tendency exists outside the medical community to see hypoglycemia everywhere and believe that health-food diets are a panacea for mental illness.

"It is difficult to explain the lack of glucose in the brain and the consequent depression and anxiety. No one really knows if it has a physiological or psychological root," says a Boston psychiatrist who has administered electric shock treatments.

"Electric shock is a last resort. It's like having a computer on the blink and, just before it destroys itself, you bash it with a sledge hammer to shake everything up inside and see where it lands. It can't hurt. Sometimes it helps."

Since it is as hard to say for certain what cures hypoglycemia as what causes it, it would be unwise to draw any broad medical conclusion from Papi's complicated case.

Papi is left with the undeniable subjective truth of what he has endured and what it has taught him.

"Nothing seems terribly worrisome to me now," he says. "That helps when you're coming off the disabled list and you haven't seen a real curve ball in BP (batting practice) all spring."

Papi gives his big smile under his big schnozz and the bright eyes. His life in a pennant race started today.

Once, it might have scared him, might have seemed like the beginning and end of the world.

"I think," he says, "that it'll be a lot of fun." CAPTION: Picture, Stan Papi