Hi
Provided you have not split and removed sections of the audio you should be able to place it back onto the timelime under the video track and move it so it synchronizes again. However, even though it originally came from the video VP sees it as a different sound clip and you will not be able to re-link it. You can however, group it with the video. This will, in effect "re-link" it. But If you make splits in the tracks the grouping between the sections may be broken and you will have to regroup any bits that come apart.
In certain circumstances editing using IN/OUT markers on the grouped sound/video clips in the clip preview window can be problematical.
VP does have some sound editing options which can be applied to the audio track which does not require the track to be removed. What sort of editing to the sound are you doing?
Nat