Baseball commissioner Bowie Kuhn testified today that one of his concerns in vetoing Charles O. Finley's attempted $3.5 million sale of three Oakland A's Players was that Finley might use some of the money to solve his nonbaseball financial problems.

"I was more than a little concerned as to how much money he was going to commit to his team because he said he had serious financial problems with his (insurance) business also," Kuhn said.

The commissioner took the stand in federal court in his own defense today in a packed courtroom that included so many of Finley's female friends that it prompted defense counsel Irvin B. Nathan to quip, "Look at Charlie's Angels."

Finley is suing Kuhn for $3.5 million for nullifying the June 15 sale of Vida Blue to the New York Yankees for $1.5 million and Rollie Fingers and Joe Rudi to the Boston Red Sox for $1 million each.

Kuhn, who will return to the stand on Thursday for further cross-examination, testified extensively on the events leading to his action a few days after Finley announced the deals within minutes of the trading deadline.

Kuhn said he was in Chicago when he learned of the sales and called Finley. "I said, 'Charlie, these deals are disasters for Baseball and I'm very troubled by them. I don't know if we cen let them go through.'

"His reaction was quite strong and he was upset. He said, 'Commissioner, you ought not to be butting into this. There's nothing wrong with the deals. No rules were broken.'"

The two met at a restaurant two hours later where Finley "argued vigorously against my doing anything," but did not challenge his authority to act, Kuhn said.

Finley told him he was having serious difficulties trying to sign Fingers and Rudi although he had signed Blue, Kuhn said. Afterward, Finley took him aside "and said in a very friendly way that I had to realize the serious financial difficulties he had and that the sales were essential to his keeping going."

Kuhn did not testify on Finley's nonbaseball problems, but it is known that he is being questioned by the Internal Revenue Service for alleged failure to pay personal and corporate income taxes for three years. He is also having financial difficulties in meeting support payments for his wife, whom he is divorcing.

Under questioning from Peter K. Bleakley, chief defense lawyer, Kuhn said he was concerned that Finley might be trying to get out of baseball and would not use the money to rebuild the team. He also said he told Finley he was an "outstanding salesman in dealing with players in the past" and that he was confident Finley could persuade Rudi and Fingers to sign.

But, Kuhn said, Finley insisted he needed the proceeds from the sales and said he planned to use some of the money to buy free agents in the fall re-entry draft. Kuhn speculated that Finley would not be able to get many, if any, because of the competition for the players and the procedure in which they were to be drafted.

Finley has never specified exactly how he would use the money but has said he would use the money but has said he would use some of it for new players, getting a radio contract, hiring scouts and covering other losses, according to defense lawyer Paul S. Reichler.

After consulting with baseball's executive council and the respective club owners involved in the deals during a meeting at his New York office. Kuhn said, he decided to cancel the sales for a number of reaspns.

"I thought it would upset competition balance, set a terrible precedent, weaken a very outstanding team and the Yankees and Red Sox could be so far advanced (in their divisional race) as to put everyone else out of competition," Kuhn said.

Saying the commissioner acts as the watchdog and the conscience of the game, Kuhn contended that he had the authority to cancel the sales under a section of baseball's constitution that allows the commissioner to take whatever action he deems in the best interest of baseball.

"The commissioner should use the authority given him to act in the best interest of baseball, to protect the integrity of the game, the honesty of it and the public's confidence in it," Kuhn said. "The powers are awesome so they have to be used with sensible, rational restraint and in good faith."

In response to Bleakley's questions, Kuhn ticked off a list of actions he has taken in other instances that involved neither rule violations nor questions of moral terpitude - the two areas Finley contends the commissioner's powers are limited to.

Under cross-examiner by Neil Papiano, Finley's chief lawyer, Kuhn acknowledged that George Steinbrenner, owner of the Yankees, challenged his authority to nullify the sales.

When asked why he did not exercise his best-interest powers to declare an arbitrator's ruling that created a free-agent system for players to be void, Kuhn said he had considered the possibility. But, he said, he decided it would be disruptive to the clubs and players and that a modified reserve system probably could be agreed upon in the contract talks that were under way at the time.