I don't know if receivers have a "pass through"... which is what you are essentially describing....
The 7/5.1 inputs on receivers are almost always analog pass-through. No delay or bass management can be applied to them. They function simply as a pre-amp to the amplifiers.
The only issue, and I doubt it will be one, is the DSP will be seeing a full line-level signal, rather than an attenuated one, that it would receive post pre-amp in the standard configuration.