A bearing assembly for a wind turbine, comprising; a bearing comprising an outer race, an inner race rotatable relative to the outer race, and a plurality of roller elements positioned within at least one raceway defined between the outer and inner races (52, 54), at least one of the outer race or the inner race defining a radial opening; and, at least one ball plug positioned within the radial opening of at least one of the outer race or the inner race, the at least one ball plug being removable such that the plurality of roller elements can be inserted between the outer and inner races (52, 54), at least a portion of the at least one ball plug comprising a tapered cross-section, wherein the tapered cross-section is positioned between an outer portion and an inner portion of the at least one ball plug so as to define a transitional region thereof; further comprising exterior retention means arranged at or adjacent to a distal-most end of the outer portion of the at least one ball plug; a plurality of O-rings arranged circumferentially around the inner portion of the at least one ball plug, wherein the inner portion of the at least one ball plug further comprises at least one annular recess, the plurality of O-rings arranged within the at least one annular recess; and the plurality of O-rings being aligned in a longitudinal direction of the at least one ball plug; and further comprising an anti-rotation device in contact with an inner surface of the radial opening, the anti-rotation device extending perpendicular to a longitudinal axis of the at least one ball plug and engaging the outer portion of the at least one ball plug so as to prevent rotation thereof. a bearing comprising an outer race, an inner race rotatable relative to the outer race, and a plurality of roller elements positioned within at least one raceway defined between the outer and inner races (52, 54), at least one of the outer race or the inner race defining a radial opening; and, at least one ball plug positioned within the radial opening of at least one of the outer race or the inner race, the at least one ball plug being removable such that the plurality of roller elements can be inserted between the outer and inner races (52, 54), at least a portion of the at least one ball plug comprising a tapered cross-section, wherein the tapered cross-section is positioned between an outer portion and an inner portion of the at least one ball plug so as to define a transitional region thereof; further comprising exterior retention means arranged at or adjacent to a distal-most end of the outer portion of the at least one ball plug; a plurality of O-rings arranged circumferentially around the inner portion of the at least one ball plug, wherein the inner portion of the at least one ball plug further comprises at least one annular recess, the plurality of O-rings arranged within the at least one annular recess; and the plurality of O-rings being aligned in a longitudinal direction of the at least one ball plug; and further comprising an anti-rotation device in contact with an inner surface of the radial opening, the anti-rotation device extending perpendicular to a longitudinal axis of the at least one ball plug and engaging the outer portion of the at least one ball plug so as to prevent rotation thereof.