A new entrant at any level should never be burdened (leave aside “overburdened”), and an ample time should be given to him to prepare himself for the forthcoming project(s). If already there is a load of work, the minimum should fall on the new entrant, rest should be shared among the existing team members. This is to avoid any shock states for the new entrant and moreover he should be given ample time to groom, adopt, accept, learn and understand.
Simple theory is that a plant that has to turn into a tree later can not bear fruits in its plan phase. No wonder if extra burden is put on the new entrant – either he will run away, or will break down. The plant will require proper care, protection, air, water and atmosphere to grow, which becomes the responsibility of the team leader, project manager. A guideline for this should already be there in place through the top management which gets into the culture of the organization and in turn in the heart and blood of the existing team members.