Higher protein fortification may result in a stiffer yogurt gel. Such effect limits the protein fortification level, because a gel with high stiffness may cause poor textural sensory attributes and poor product processability. In the current research, a partial calcium depleted milk protein concentrate 80 (CD-MPC) was manufactured. It may be used as protein fortifier in high protein yogurt without increasing gel firmness as much as a standard MPC80 (Std-MPC). Textural, rheological and stability properties of the fermented yogurt gels were characterized for presenting the functionalities of CD-MPC. The calcium content of CD-MPC is lower than a Std-MPC (P < 0.05). CD-MPC and Std-MPC were applied into 4 different fat-free model yogurt gels respectively; the 4 different models are discriminated by 4 protein contents: 4%, 6%, 8%, 10% (wt/wt). In each model, nonfat dry milk powder was used as the base ingredient for contributing 3.5% protein content and either CD-MPC or std-MPC was used for compensating the rest protein content for each model. Textural analysis results showed that using CD-MPC instead of using Std-MPC may result in relatively lower firmness, consistency, cohesiveness, and viscosity (P < 0.05) in the models containing no less than 6% protein. Steady-state shear viscosity and dynamic oscillatory strain sweep measurements were used for characterizing rheological properties of yogurt gels. For the higher protein models, the flow behavior curves were well separated between the test and control samples, the test samples were relatively less viscous. A similar trend was observed in the strain sweep tests, CD-MPC containing gels showed lower storage modulus and loss modulus. Both textual and rheological results confirmed that CD-MPC may result in a weaker gel when compared with Std-MPC. In the stability study, the results showed that CD-MPC may result in improved water holding capacity (WHC) compared with std-MPC. Overall, the current results suggest that the CD-MPC is a promising protein fortifier which may be used for improving gel stability without highly increasing gel firmness of protein fortified yogurts.