Parkes spent four months on loan with Rovers last season and is now closing in on a permanent move.
The 20-year-old is a product of the Foxes youth academy and has had loan spells with Burton (pictured) and Yeovil.
"We are delighted to be bringing Tom to the club," manager Mark McGhee told the club's official website.
"He is a left-sided centre-half which will give us great balance playing alongside either Garry Kenneth or Adam Virgo.
"He proved last season that he can play as well, and he will be a great addition to strengthen our defence."