Not easily. You’d need to get a device that converts an analog signal from the CD player into an HDMI ARC or eARC signal, and then a switch between that device and your TV’s ARC connection. You’d probably have a better chance of connecting your CD layer to an input on the TV, and use the TV set as your switch device. If you have the analog inputs on your TV set. Of course, that means the TV would need to be turned on when listening to CDs.

Alternately, the more common solution would be to add a Sonos device to your system that has an analog input, either a Five, or a Port, that you could then connect your CD player to. 

Thanks for your quick reply. Someone did suggest using a Blu-ray player to play CD’s. I am not sure if the audio quality of a Blu-Ray matches that of a dedicated CD? Any thoughts?

There's no technical reason why a Blu-ray player should play CDs better, or worse, than a CD player. CD and DVD players have a red laser. Blu-ray players have both a blue laser and a red laser, and will use the appropriate one based on the media being played. 

If the Blu-ray player is a higher quality player than the CD player, yes it could sound better if it has a better transport mechanism and digital-to-audio circuitry. Since Blu-ray players have to play high resolution audio from Blu-ray discs, the DAC chip is probably better than your equivalently priced CD player.

That said, a high quality CD player will also beat a cheap Blu-ray player, so it all depends.

Super….again…..thanks for you excellent answers!

If I wanted to keep my cost down, would a used Connect work instead of a Port?

Yes, a Sonos Connect would work fine using its Analog line-in from the chosen player.

Note: the post-2015 Sonos Connect‘s are S2 compatible  but earlier models may work only on the Sonos S1 platform, so you may want to check that matter with the seller, depending on your own system requirements.

Yes, as long as it’s a Gen2, so built after 2015. Those can be played with the S2 software that you need for the Arc.