Setting Center on Subwoofer..

[TP83]

Hello. Im almost out of room in my living room/theater and it would really be a benefit space wise to set my sub in front of my tv and lay the center channel on top of it. I know it would vibrate the center, but would that greatly decrease sound quality? More importantly would it mess the center channel up? This may be a dumb question, but thanks in advance for any help.