The Sky Bet League One club have moved quickly to draft in Toffolo, 22, as replacement for summer signing Danny Andrew, who has been ruled out for the season due to a knee injury.
Andrew damaged a cruciate ligament in the third minute of last weekend’s defeat at AFC Wimbledon but played on for the full 90 minutes without knowing the full extent of his injury.
“Harry has good experience in League One, he has played over 50 games in the competition, he was one of the targets alongside Danny Andrew during the summer,” Rovers boss Darren Ferguson told the club’s official website.
“We worked quickly to get Harry in after we knew how long Danny would be out for, we felt we needed someone in that left side of the defence and he ticks a lot of boxes with his experience in League One and he is used to playing a lot of different formations.”
Toffolo has made only two senior appearances for Norwich, but has yet to feature for them this season. He has had previous loan spells at Swindon, Rotherham, Peterborough and Scunthorpe.
Rovers completed a deal to bring Chelsea midfielder Jordan Houghton back to the club on a loan deal until January earlier on Thursday.