Wire the CD player to the Line-In on either speaker of the stereo pair. It’ll play stereo on both. 

Brilliant, thanks Ratty! So no need for an amp between the cd player and the speakers? Any advice on type of connection cables??

Most likely the cable will be RCA to 3.5 mm. 
 

Click the link for an example:
https://www.amazon.com/Amazon-Basics-Adapter-Subwoofer-Gold-Plated/dp/B01D5H8JW0/ref=mp_s_a_1_1_ffob_sspa?crid=37V6HW4KFULIT&keywords=rca+to+3.5mm+male&qid=1697037612&sprefix=rca+to+3%2Caps%2C140&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfYXRm&psc=1

No need for an amp.  More than likely the CD player has RCA outs.  So you would need an RCA to 3.5 mm stereo miniplug cable. 

RCA to 3.5 mm stereo cable.

I thought I’d like to play my CDs too, folks here showed me how to rip them to my computer and then share them to Sonos using the Music Library. No more changing CDs and I can chain a lot of them together in the queue or a playlist instead. CD storage cabinet hasn’t been open in years.

As long as you rip to a lossless format, FLAC is my choice, there is no difference in the sound.

Thank you for the heads up and advice. I can now proceed with purchasing a cd player and dusting off my cd collection.

Hi @Rockhouse86  Did you manage to buy a Marantz CD6007 player and connect it to Sonos? I would like to have/buy the same device, that's why I'm asking. Thank you…

Whelther or not @Rockhouse86 purchased the Marantz CD6007 is irrelevant. The question was answered by @jgatie as affirmative for the connection. I also provided a link to the type of cable required. Also it’s verified in the link below that the player has RCA out.

All said what is your specific connection question/issue and what type of Sonos gear is involved? More information will help as there is another option if you don’t own a Sonos speaker with line-in.

https://www.worldwidestereo.com/products/marantz-cd6007-single-disc-cd-player-with-usb-port?variant=46684744515895&gad_source=1&gbraid=0AAAAADzok1_X7gcUDSGiUtbqg8Ydpt0sT&gclid=EAIaIQobChMIpZKqs7G5gwMV151aBR27MgHzEAQYASABEgK3V_D_BwE