A modular shoulder prosthesis system, in at least one embodiment, provides flexibility in shoulder replacements and ability to switch between a traditional anatomic Total Shoulder Replacement (ta-TSR) to a reverse Total Shoulder Replacement (r-TSR). Optionally, the system provides for a modular adaptation for the glenoid side in a Total Shoulder Replacement (TSR). The system includes a baseplate, a modular component, a humeral stem and a modular humeral component. The baseplate includes a base with a pair of notches extending down from the top surface on opposed sides of the base. The modular component and the modular humeral component configured to cooperate with each other. The baseplate is capable of attachment to different modular components and the humeral stem is capable of attachment to different modular humeral components to facilitate both ta-TSR and r-TSR with a change in the modular component and change in the modular humeral component.
