Using Pioneer DDJ-SX and Laptop's own soundcard for a 3rd line in?

Hey guys, my question is simple.

Using Traktor Pro 2 on my laptop (Sony Vaio with Windows 7 64-bit), USB connected to DDJ-SX's  channels 1 and 2.

Can I still use for ex. Spotify in the same laptop with headphone jack audio out for channel 3? I would be using a 3.5mm jack to RCA cable here.

Thanks in advance!