We have studied the effects of optical pumping and near-resonant radiation pressure that compete with the saturation effect on the formation of the line shapes of Doppler-free saturation absorption spectra of alkali atoms. We have measured the reverse of the sign of Fg=3 to Fe=4 saturated absorption of the rubidium D2 line and the change in its asymmetry as the optical pumping effect is gradually turned on compared with the saturation effect. The experimentally observed behaviors of optically pumped Lamb dips and crossover resonances in rubidium show good agreement with the calculation using the phenomenological model previously introduced for cesium.