A modal-like projection method for poroelastic materials is proposed and implemented for finite element calculations. Nonphysical Dirichlet conditions are imposed at the junction interface, involving constrained fluid displacements and free solid displacements. The $(u^s,U^f)$ formulation is used. The resulting frequency-dependent eigenproblem is solved without simplification using the non-linear Arnoldi algorithm. The projection subspace is spanned by calculated dynamic modes and fluid static boundary functions. A convergence study is performed and results are compared to classical Craig and Bampton and MacNeal approaches. The hybrid basis proves to be efficient.