A Relationship Gets Worse in New York : Basketball: The departure of McDaniel to Celtics is the latest grounds for hard feelings between Knick president and an agent.

The two Davids, as they say in background briefings, have a history. They had one before New York Knicks President Dave Checketts wiped the breakfast egg off his face Thursday and reached agent David Falk in Boston, where client Xavier McDaniel was about to sign a contract with the Boston Celtics. In the aftermath of that deal, one that punched a hole in the Knicks’ front line and championship aspirations, the relationship may be irreparably damaged.

Certainly, the ability of the men to conduct future negotiations has been compromised. So where do they go from here? “That may be the question of the day,” Checketts said hours after the Knicks’ only small forward agreed to work for a division rival. “I think you can answer it yourself.”

They never were the best of friends, dating to a confrontation when Checketts was running the Utah Jazz and Falk was advising Adrian Dantley not to report to training camp. That was in the back of the executive’s mind when he was hired to reorganize the Knicks March 1, 1991. At the time, Checketts said his first priority was to negotiate a new contract with center Patrmck Ewing, the cornerstone of the team and one of Falk’s more prominent clients.

“David Falk and I have had our problems in the past,” Checketts said, “but we agreed to push them aside.” Despite a pledge of $33 million for six years, Ewing did not sign. In fact, he filed a grievance in an attempt to free himself from the last four years of his old contract.

The arbitrator ruled against Ewing. Yet, in an effort to keep the player happy, the Knicks offered him a two-year extension for $18.8 million, raising his total salary over six seasons to the $33 million they previously had offered. When Ewing signed in November, he became -- temporarily -- the highest-paid athlete in a team sport.

By then, Checketts and Falk had been brought together again by a trade in which the Knicks obtained McDaniel from the Suns for Jerrod Mustaf, Trent Tucker and a pair of second-round draft picks. The X-Man said he was happy in New York right up until that day in January when he exercised a buyout clause in his contract, allowing him to become an unrestricted free agent after the season. It cost him $500,000 as well as the security of two guaranteed seasons, at $1.8 million apiece.

“We made it clear to his agent we didn’t trade for X for one season,” Checketts said then. “I have every confidence we will sign him and bring him back.” And that was before McDaniel, who endured a very inconsistent season, sparkled in the Knicks’ energizing playoff run against the Pistons and Bulls.

There never was any doubt in his mind, Checketts said, that the man would be back in a Knicks uniform this season. The team held off re-signing him only because there was flexibility under the salary cap to sign another prominent player or two before locking in its own employees. So Checketts went after the Washington Bullets’ Harvey Grant, a restricted free agent. When the Bullets matched the offer, the executive constructed a three-team deal in which the Knicks would receive Charles Smith and others from the Clippers.

Alas, Stanley Roberts, the center who was slated to go from the Orlando Magic to the Los Angeles Clippers, exercised his right and blocked the trade. While management of all three clubs attempted to assess the fallout, Falk and McDaniel flew to Boston and agreed to a three-year contract within the space of 24 hours. Checketts said he and Falk had communicated all summer and had d’a very positive negotiating session last week.”

Indeed, he said, “I thought I had a gentlemen’s agreement with Falk.” It was Checketts’ understanding that if Falk talked to any other teams, he would give the Knicks an opportunity to match the offer. Checketts said he was prepared to do better than that, was prepared to offer McDaniel more than he settled for in Boston, starting at $2 million for the first year. He also recalled that Falk had used the words “good faith” in the Knicks’ treatment of Ewing and had pledged the same when it came to McDaniel.

That’s why the Knick president almost choked on his breakfast when he heard the Celtics had called a news conference to announce their replacement for the retired Larry Bird. He drove to coach Pat Riley’s house nearby and, from there, finally tracked down Falk by telephone. The agent said it was too late, that the Celtics made his client “feel wanted.”

Checketts said he told Falk, “You showed me what you call ‘good faith’ negotiations.” But the damage already was done.

It won’t bother Falk to be a villain in New York. He operates out of Washington. And it’s difficult for fans to get worked up afout an agent. The David who takes the heat for this mistake is Checketts, who suffered his first setback after 18 months of progress, whose building plans have been disrupted, who must answer to Stanley Jaffe and the directors at Paramount. Through no fault of his own, he didn’t get Grant and he has yet to land Smith, two forwards who would greatly enhance the Knicks’ front line.

And now there is an O where X used to be. “I know there’s going to be some people upset at this,” Checketts said. “I’m upset.”