The Supreme Court agreed Tuesday to decide whether employers ever may bar their workers from serving in the military or military reserves.

The justices said they will review a ruling in an Alabama case that said an employee's request for a military leave may be denied if it is "unreasonable."Although the court's action in the military reserves case comes at a time when more than 200,000 reservists have been called to active duty because of the Persian Gulf war, they will not be affected directly by the decision, expected sometime in 1992.

Separate sections of a federal law deal with reserve duty for training and a call for reservists to active duty in time of crisis.

In another case, the justices agreed to decide whether federal courts should continue supervising the racial desegregation of student populations in DeKalb County, Ga., public schools.

The court will review a ruling that says continued judicial supervision is required because the county schools never achieved full integration.

The court's decision, expected by July, could provide important new guidelines as to just what amounts to full racial integration of a school district.

In a separate action, the court let stand rulings that Denver's public schools have not yet achieved full integration. The justices, without comment, refused to free Denver school officials from a federal judge's continuing supervision.

In other action Tuesday, the court:

- Agreed to decide whether states may compensate crime victims by seizing profits paid to criminals for books, movies and other accounts of their exhibits.

Setting the stage for an important ruling on freedom of expression, the court said it will study a challenge to such a New York law by the publisher of a best-seller on organized crime.

- Made it easier for some convicted criminals to challenge their convictions in federal court.

The court unanimously ruled that Georgia death-row inmate James A. Ford is entitled to a federal court hearing to decide whether blacks were excluded unlawfully from his jury.

- Left intact the federal government's random drug-testing program for airline workers.