Gov. Marvin Mandel's doctors said yesterday the Maryland governor had suffered a "small stroke" and must be hospitalized for two weeks, making it impossible for him to go on trial next week on charges of political corruption.

U.S. District Judge Robert Love Taylor, acting on a request by Mandel's attorney, Arnold Weiner, set a hearing on "the governor's health problems" for 9 a.m. Tuesday, the day before the governor's second trial is scheduled to begin. Weiner is expected to file a formal motion Monday requesting a delay in the trial.

"We have a gentleman who is convalescing from a small stroke," said Dr. Marvin Korengold, a neurologist on the faculty of George Washington University Medical School. He said Mandel also must avoid "undue stress and strain" for two months after he leaves the hospital.

This set off the first murmurs in Annapolis of a need for Mandel to name Lt. Gov. Blair Lee III "acting governor" while Mandel recuperates. If Mandel is unable to return to the State House after he leaves the hospital, it would "obviously create a very serious problem" and he should "give strong consideration" to naming Lee acting governor, said Del. John Hanson Briscoe, speaker of the House of Delegates.

Mandel's three doctors, however, indicated that the governor may be able to perform "routine duties" after a period of hospital rest as long as he avoids tense situations, like courtroom appearances.

"We might recommend that (returning to work) as occupational therapy," said Mandel's family doctor, Perry Hookman.

Mandel's ailments, the doctors said, result from a stroke, or other circulatory problem, and are not obvious to the layman.

"He has a little loss of strength in his right arm; he's lost the grip in his right hand, and he's lost dexterity in his right foot. You can tell it in terms of his walking," Korengold told a news briefing at Prince George's General Hospital. "It's mild, it's subtle, but there's no doubt it exists."

The briefing, attended by Hookman, Korengold and a third specialist called into the case, Dr. George B. Udvarheyi, as well as the governor's wife Jeanne, and his son Gary, was the first definitive word on the governor's condition since he was hospitalized Tuesday, suffering from fatigue.

A series of tests, Hookman said, found Mandel's illness resulted from "a disorder in the left hemisphere of the brain." This could have resulted either from a stroke, or other circulatory disorder, such as a blood vessel spasm.

A stroke, according to doctors, occurs when the blood flow is cut off or reduced to a part of the brain. As a result, nerve cells in that part of the brain cannot function, and the parts of the body controlled by the nerve cells do not function either.

The common signs of a stroke are problems in controlling limbs or speaking.

Mandel has long had a slight diabetic condition that makes him more susceptible to strokes. He takes an oral medication for the condition.

The doctors yesterday were unable to pinpoint when Mandel's stroke occurred, although they indicated it was sometime within the last eight weeks. It is not unusual for doctors to be unable to do this.

The danger in his condition, Korengold said is "anyone who has had one stroke is more susceptible to a second."

The timing of the ailment, however, is certain to raise even further questions. Mandel and five codefendants were scheduled to go on trial for the second time on charges of political corruption April 13, eight days after the governor was taken to Prince George's General Hospital in Cheverly.

The trial has been delayed three previous times, most recently in Devember when two jury-tampering incidents resulted in a mistrial.

The governor is the second defendant in the corruption case to develop health problems. Last September, the trial of Irvin Kovens, a close Mandel associate, was separated from that of the other defendants and postponed after he developed a heart ailment. Kovens is scheduled to go on trial with the other defendants this time.

Mandel was not told until yesterday morning that he would have to remain in the hospital two more weeks. "I think he's somewhat depressed that he has to undergo this," said Hookman. But, the doctor added, "he's still optimistic, he's still cheerful. He's still raring to go."

The doctors insisted that Mandel's condition was being treated like any other patient's. "If he weren't the governor, we'd say the same thing," Korengold said at one point. "If the patient were any man other then Gov. Mandel, I would say he definitely would not be able to stand the stress of another trial," Hookman said at another juncture.

Hookman said Mandel will be treated with a drug to thin his blood and reduce the pressure that caused the stroke. The drug is not a strong one and won't keep the governor from working, he added.

Mandel apparently would still be able to move about and read and write without difficulty. The governor writes with his left hand, which hasn't been affected by the disorder.

Jeanne Mandel expressed some relief that her husband's condition wasn't more serious. "At least we know what it is now and we can treat it," she said.

As for the trial, she said. "I'm not even thinking about that. He has to take the doctors' advice and get well. He is in no way happy about staying in the hospital."

Jeanne Mandel insisted that her husband, with her help, will be able to keep his hands on the reins of government. "As long as he has me running back and forth, the state will not suffer at all," she said.

But there was a marked change in mood in Annapolis. An air of expectation surrounded Lt. Gov. Lee as he moved around the State House. Lee, who has long served in Mandel's shadow and is an announced candidate in the 1978 election to succeed him, emerged as the leader in pushing Mandel's legislative program through its final rough days in the legislature this week.

Publicly, Lee dismissed suggestions that he should be named acting governor in Mandel's absence. "I'm not going to talk about that," he said. "My only interest now is getting through this session" of the General Assembly, which ends Monday.

Technically, as long as Mandel remains in the state, there is no need for him to designate Lee acting governor. The title of acting governor, which can be granted by a letter, would confer all the powers and dutires of the office, but not the salary on Lee.

Such a transfer of power would become necessary if Mandel were absent from the State House for an extended time, said House Speaker Bricoe. "It would seem the office would be incapacitated," he stid.

In an interview Thursday, Jeannie Mandel said she first began noticing her 56-year-old husband's health problems two months ago when he began complaining of being overly tired. According to her, Mandel frequently had trouble sleeping, and would wander about the governor's mansion at night.

"He kept saying, "I think I either mattress," she said.

Mandel also complained of momentarily losing his memory at several points, she said, and about a month ago she persuaded him to visit their family physician, Hookman. She said she noticed the pressures building on Mandel as the legislative session become more heated last week.

Some observers who saw the governor during this period thought he looked wrong, but he struck others as looking vigorous and healthy. He kept up his duties, including entertaining 25 guests at the mansion Sunday night, and testifying before two congressional committees in Washington Monday.