The 19-year-old spent the back end of last season on loan at MK Dons, making 13 appearances, and also had spells at Forest Green and Chesterfield.
Foxes boss Martin Allen told the club website: "I have seen Jonathan play for Reading reserves on numerous occasions.
"He has pace, he is direct and he is very confident. I took him with me to on loan to MK Dons. He was impressive."