The defense in the case of a Philadelphia caterer accused of selling cocaine to major league baseball players suffered a major setback today when the presiding judge indicated he would not let defense witnesses testify about peripheral issues, specifically amphetamines.

The development came after the prosecution rested its case against Curtis Strong and two of the 16 counts against the defendant were dismissed at the request of U.S. Attorney J. Alan Johnson because "those counts were not established" in testimony.

A motion by defense attorney Adam Renfroe Jr. to dismiss a third count was denied by Judge Gustave Diamond, as was the defense request for a directed verdict of acquittal.

The defense is expected to begin presenting its case Tuesday morning.

Although Diamond said he was not making a formal ruling at this time, he made it clear to Renfroe that he would not allow as broad a scope of questioning as he did during cross-examination of government witnesses.

Citing previous cases, Diamond said that Renfroe was able to ask the players about amphetamines, because "the widest latitude" is given to the defense in cross-examination.

Renfroe's main strategy throughout this case, which is in its third week, has been to discredit the players, whom he has called "hero-criminals." To this end, he has elicited testimony from Lonnie Smith that Pete Rose and others might have used amphetamines and from Dale Berra and Dave Parker that Willie Stargell and Bill Madlock dispensed the stimulant to their Pittsburgh Pirates teammates.

Rose, Stargell and Madlock have denied such accusations.

Renfroe, who today declined to say which players he would call to testify, has said he might call Rose and Stargell. "Be here tomorrow at 9:30," Renfroe said. "It'll be very interesting."

Asked if he thought he would not be able to call Stargell and Madlock, Renfroe replied, "No, there's always another way to skin a cat."

Even if a witness is called to the stand, he might not be allowed to testify if Renfroe cannot make a sufficient "offer of proof" as to his basis for calling that witness.

For the second straight session, court was recessed early, as Renfroe, expecting the prosecution case to last another day or two, was granted a delay.

The prosecution called 18 witnesses in trying to build a strong circumstantial case against Strong. "Any case you have without narcotics in hand is a very difficult case," Johnson said. "That's why there was immunity granted (to at least a dozen current or former players) in this case."

One of today's witnesses, Jack Brook of Bell of Pennsylvania, established that the phone number Smith had called in Philadelphia was Strong's. Testimony also revealed that Strong's phone was disconnected for nonpayment of his bill.

Renfroe said he would establish an alibi defense for his client. "I have an alibi defense on every count there is." Asked if that meant he had witnesses to testify Strong was not in Pittsburgh on the dates in question, Renfroe said, "They haven't proved on documentary evidence that he was . . . The burden of proof rests on the government."

Meanwhile, jury selection began in the cocaine-trafficking trial of Robert McCue, one of seven men indicted May 31 by a federal grand jury here. A jury is not expected to be chosen before Wednesday.

McCue, 38, of Pittsburgh, is charged with 13 counts between June 1983 and January 1985. Berra, John Milner and Rod Scurry are players or former players listed by the government as potential witnesses in the case.