You could, but if you played it together with the speakers that are connected to the receiver, it will lag behind by 75ms, causing an echo. 

Thanks, i was planning on using my Sonos equipment as a different zone

Different Zone? I’m not sure but in a different room of your home they would be good.

I connected my Play5 to zone 2 out, cannot make it work. Are there any settings I need to change in Sonos app.

Are you sure the Zone 2 Out ports are providing an audio signal? You can test that using a set of headphones.

If there is audio are you selecting the Line-In on the Play 5 and is the cable fully inserted?

The PLAY:5 Line-In is not automatically passed through to the speaker. Line-In is simply a network resource. You must select Line-In as the source for the PLAY:5. 

I got it going, forgot I had to select line in the app.

 Thanks