On a winter night in his Tampa, Fla, home, Lou Piniella can be found anytime by his wife Anita standing in front of a full-length mirror pumping his 34-ounce bat back and forth, back and forth, his darkly handsome face set in stone at the imaginary pitcher in the glass.

"The first time I roomed with him," said former Yankee catcher Fran Healy, now a broadcaster, "it scared the hell out of me. I wake up in the middle of the night and I see some big guy reflected in the mirror, with a big stick in his hand."

Roommates have learned to tolerate Piniella's fetish for swinging that bat at any time or any place. Anita Piniella accepts it because it pays the groceries.

"I pump the bat a lot," says Piniella, "because I don't want to forget how. If I stop hitting the ball I'll have to drive a truck."

It was Piniella's sinking line drive that Bill Russell dropped in the crazy Yankee sixth inning, picked up and then hit Reggie Jackson with his throw, and it was Piniella's single that won it.

It happens that way so often that the Yankees come to expect miracles from Piniella's bat. He is one of the most dedicated hitters in the game.

"He studies hitting as good as anybody I ever seen," said Yogi Berra, the Hall of Famer, Yankee hitting instructor and one-time pretty fair country hardball hitter himself.

"I have these different stances," said Piniella, who is never satisfied with one stance in any single at bat and certainly not in any game. "I like to stand close to the plate for right-handers and a litter farther back for left-handers."

The 35-year-old Yankee right fielder had always been a good hitter. In the last three or four years he has also become an excellent fielder after being labeled "good hit, no-field" early in his career at Kansas City.

"It's just that hitting came easier to me," he said. "I never could run all that well, so fielding was tough."

Piniella is a gregarious fellow who thinks nothing of standing up gefore a crowded mass of reporters after the toughest of losses and explaining his play. It is typical Yankee reaction.

"I enjoy people, I enjoy talking," he said. "I like to have a good time."

Piniella is not against a beer once in a while, a day at the race track or a tough game of cards for entertainment. He is also famed on the Yankees as the best needler on the club.

When Catfish Hunter was suffering from a sore arm, Piniella once put three helmets on his head before a game and announced, "I'm going out to right field. The Cat is pitching. I gotta protect myself from those bombs."

Hunter always had a steady answer for Piniella, repeated over and over again whenever Piniella's needle grew sharp.

"Jim Unprintable Wohlford," he would say, repeating the name of the journeyman outfielder who took Piniella's job in Kansas City and freed him for a Yankee trade.

Piniella, who is the Florida-born son of Spanish-born parents, is hot-tempered when things don't quite go his way.

Earlier in my career they wouldn't allow me near the bat rack," he said. "I broke too many of them."