There's a breakout cable that allows RCA Left and Right audio in, so I don't see why not. However, you'd need line-level, aka pre-amp output from your receiver. You couldn't send it amplified signals; that would seem to be impossible. Does your AVR allow pre-amp outs on a per-channel basis?
By the way, we have a center-channel issue too and are re-configuring our cabinets to accommodate the VT50. (The older Panasonic sat taller and therefore I could sit my center channel directly in front of it no problem). As a result, we've used the TV speaker for the entire ownership period to date, which is unheard of for us. It sounds actually pretty decent and I imagine it would make for a quite adequate center channel.