Rotational vibration is usually always wheel/tyre/brake related in spite of how these components look visually. And in some extreme cases, knackered outer CV joints......but you haven't said if it occurs at a specific road speed, or if it's rpm based, or if it's only felt on the steering wheel, and/or in the chassis as well.
I would confirm/deny warped discs with a dial gauge. People assume it's not the brakes if they were recently changed, but if the hub face wasn't spotless, or if the wheels over torqued and not tightened in a load reducing sequence (opposite pairs) then it could very easily be a warped disc. Or pad deposits as mentioned above. If the disc looks nicely polished on both sides with no visible 'high spots' or localized discolouration, it's probably not that.