  We investigate the injection of quasiparticle spin currents into a
superconductor via spin pumping from an adjacent FM layer.$\;$To this end, we
use NbN/\ch{Ni80Fe20}(Py)-heterostructures with a Pt spin sink layer and excite
ferromagnetic resonance in the Py-layer by placing the samples onto a coplanar
waveguide (CPW). A phase sensitive detection of the microwave transmission
signal is used to quantitatively extract the inductive coupling strength
between sample and CPW, interpreted in terms of inverse current-induced
torques, in our heterostructures as a function of temperature. Below the
superconducting transition temperature $T_{\mathrm{c}}$, we observe a
suppression of the damping-like torque generated in the Pt layer by the inverse
spin Hall effect (iSHE), which can be understood by the changes in spin current
transport in the superconducting NbN-layer. Moreover, below $T_{\mathrm{c}}$ we
find a large field-like current-induced torque.
