The 18-year-old has yet to make a senior appearance for Palace but has represented England at youth level.
Robins boss Mark Yates told the club's official website: "He's a towering defender and will add good competition.
"He's here for an initial month but he's a good player and we're pleased to have got him. He's tall, strong and has good ability on the ball. It's another good signing for us."
- Sports & Recreation