Brett Flashnick / AP file U.S. Army Spc. Simran Lamba, center, the first enlisted Soldier to be granted a religious accommodation for his Sikh articles of faith since 1984, stands in formation with fellow soldiers before taking the oath of citizenship, prior to his graduation from basic training at Fort Jackson, S.C., in 2010.

The Pentagon on Wednesday is expected to announce widespread changes to rules governing religious items and religion-based physical attributes that service members can maintain while in uniform — including beards, some religious tattoos, and turbans.

NBC News obtained an early draft of the new Department of Defense instruction which states that the military will make every effort to accommodate “individual expressions of sincerely held beliefs” (conscience, moral principles, or religious beliefs) of service members.

It goes on to say that unless doing so could have an adverse impact on military readiness, unit cohesion, good order and discipline, health and safety, or any other military requirement, commanders can grant service members special permission to display their religious articles while in uniform.

Requests for religious accommodation can be denied when the “needs of mission accomplishment outweigh the needs of the service member,” the directive will explain.

Earlier this month, a major in the U.S. Army who is a Sikh American took his case to staffers on the Hill, explaining how he and other Sikhs should be able to serve in uniform and still maintain their religious beliefs, including wearing turbans and unshorn hair, including beards.

The new directive will explain that if the articles of faith or physical attributes interfere with the proper function of protective clothing and equipment, the request could be denied. For example, a beard or unshorn hair cannot interfere with gas masks or helmets.

Jewish service members can request permission to wear a yarmulke while in uniform. Muslim service members can request to wear a beard and carry prayer beads. Even Wiccan service members, those who practice "Magick," can seek accommodation — the directive covers all religions recognized by the U.S. military.

The policy will also spell out that service members have the right to observe no religion at all.

According to Defense Department statistics, which are based solely on self-reporting, there are only a handful of Sikh Americans in the military (about 3).

There are nearly 3,700 Muslims, nearly 6,300 Buddhists, and more than 1,500 Wiccans.

The immediate commander can approve some of the religious accommodation, but some will have to be kicked up to higher headquarters.

In some cases wearing something that impacts the uniform (religious apparel), grooming (beards, longer hair), religious tattoos, and some jewelry with religious inscriptions.

The directive stresses that “the importance of uniformity and adhering to standards, of putting unit before self, is more significant and needs to be carefully evaluated when considering each request for accommodation.”

It goes on to say that “it is particularly important to consider the effect on unit cohesion.”

Each individual service member has to re-apply for new permission at each new assignment, transfer of duty stations, and for each deployment.