Baseball may have to spend a second consecutive summer in court defending an investigation of one the game's most prominent people.

George Steinbrenner reportedly is sufficiently worried about his future as New York Yankees owner that he is planning to challenge baseball's probe of his relationships with self-described gambler Howard Spira and former Yankees outfielder Dave Winfield. Steinbrenner will allege the investigation was biased, the New York Times reported yesterday. A report in today's editions of Newsday added that he will submit additional information to Vincent before the end of the day Monday. Steinbrenner's attorney, Stephen Kaufman, would not comment on the nature of the information.

Washington attorney John Dowd led the investigation on behalf of Commissioner Fay Vincent. Last year Dowd led baseball's investigation of gambling allegations against Pete Rose.

Rose ended up pursuing what became an extended and complex lawsuit in which he accused then-commissioner A. Bartlett Giamatti of prejudging the case. Rose eventually abandoned the suit as part of a settlement under which he accepted a lifetime ban from baseball that could be appealed after one year.

Citing a source it said "is familiar" with Steinbrenner's defense, the New York Times reported Steinbrenner plans to attack Dowd's impartiality.

Dowd's investigation of Steinbrenner "was very biased and there are a lot of things that show up in terms of the bias in the Dowd investigation," the Times quoted its source as saying.

The investigation stemmed from a $40,000 payment Steinbrenner made to Spira, who has worked as a sports stringer for New York radio stations and as an aide to Winfield's former agent, Al Frohman. Spira has alleged the payment was made in exchange for information that would discredit Winfield and the David M. Winfield Foundation, a charitable organization for children.

Steinbrenner, who feuded with Winfield over baseball matters and over the foundation, has said he paid Spira the money "out of the goodness of my heart."

On July 5 in a federal court in Manhattan, Spira pleaded not guilty to charges of attempting to extort money from Steinbrenner and threatening Steinbrenner and Vincent.

On that same day, Steinbrenner began a hearing before Vincent, who is attempting to determine whether Steinbrenner committed acts "not in the best interests" of baseball. The penalty for committing such an act could involve a suspension. Steinbrenner provided Vincent with about 10 hours of testimony over two days.

At the hearing's conclusion Vincent said he was investigating the circumstances surrounding Steinbrenner's payment to Spira as well as the relationships between all three principals.

One of the reasons Steinbrenner believes Dowd's investigation was biased, the Times's source said, is that it did not sufficiently examine the relationship between Spira and Winfield. Spira has told the New York Daily News that Winfield lent him $15,000 in December 1981 to pay off gambling debts. Jeffrey Klein, the New York lawyer now reprsenting Winfield, has said Winfield did not know Spira was a gambler at the time the loan was made.

Dowd could not be reached for comment, but baseball appears satisfied with his investigation.

"It seems to me that people who have something to say publicly ought to speak to the merits and not to the techniques of the investigation," Vincent told the Times.

When the commissioner's powers have come under legal attack in the past, federal courts routinely have ruled in baseball's favor. Rose began his challenge in state court, and intitially received a ruling in his favor.

But baseball had the case moved to federal court, and Rose failed in a bid to have it sent back to state court. He chose not to pursue the matter in federal court.