In this study, we present a technique for T1rho mapping of myocardium using a combination of T1rho preparation, radial sampling, and low rank-based compressed sensing (CS) reconstruction. We acquire free-breathing, ungated data using a 3D T1rho prepared radial acquisition scheme with different spin lock times (TSL). After retrospectively synchronizing the data to a window in diastole, a sparse 3D k-dataset is given as input to compressed sensing reconstruction that uses a low rank constraint. Mono-exponential modeling of the reconstructed data yields the T1rho maps. The CS reconstruction results in improved images and the mean T1rho values estimated in the myocardium are consistent with literature.