The stage where the yeast cells are resting is known as "quiescence." The stationary phase occurs when the yeast cells have reached maximum cell density or carbon has become limiting (sugar is carbon bound to water; hence, the term carbohydrate). During the stationary phase, reproduction is for replacement only.
The risk of oxygenation is low until the yeast cells have been filtered from the beer. Any yeast cells that are still in suspension during transfer will rapidly consume any O2 that is picked up. The decision to rack should be made on what one wishes to accomplish. When bottom cropping, the beer should be racked into a maturing vessel shortly after fermentation has subsided. One does not want the yeast cells that are still in suspension to settle into the crop, as those cells usually have lost their ability to floc (aggregate), which is a common mutation.
Separating the medium floculating cells from the early floculaters in the crop can be accomplished by swirling, allowing the heaviest fraction to settle, and cropping the topmost 250 to 350 milliliters of the liquid fraction. Most of the cells in that part of the crop should be medium flocculaters that are still viable.