A liner cap assembly is disclosed for use in a gas turbine engine combustor. The assembly includes an outer ring that extends along an axis. Multiple struts are circumferentially arranged about an inner diameter of the outer ring and extend radially inwardly therefrom. A plate is supported by and axially aligned with the struts. The plate includes multiple circumferential openings that support a collar and a premix tube at each of the openings. The plate is arranged between leading and trailing edges of the struts to provide a stiffened liner cap assembly that is robust and resistant to the vibrations typically found in dry low NOx systems.