Yes you can!
Our shufflers will work with un-sleeved cards, however as they are designed for sleeved cards, it may grab additional cards at a time, and might need a slight adjustment if you plan to use primarily un-sleeved cards. Also, please be aware that with un-sleeved cards, the edges of your cards are unprotected, and the cards may catch each other on those unprotected edges at times, however it should not bend an un-sleeved card.