Abstract: An inventory system has mobile drive units that freely and independently move about a facility to transport inventory holders. The mobile drive units may operate through communications with other drive units, or under a more centralized control of a management module. For various operating scenarios, the mobile drive units are directed to shuffle the inventory holders in a manner that minimizes travel of the mobile drive units, thereby improving overall system efficiency. One or more single mobile drive units may be used to transport inventory holders to and from a region, and one or more other mobile drive units may be used to reposition or slide each of the inventory holders back and forth within the region to efficiently place inventory holders before an operator on an as-needed basis.