Both players were forced off in the weekend's victory over Stuttgart, with Hummels suffering from a gastrointestinal problem while Reus came off with a hip issue, but Terzic has expressed optimism over their availability for the second leg.
Thorgan Hazard would be the most likely candidate to deputise in Sancho's absence, but Ansgar Knauff surprisingly started at the Etihad and bagged the winner against Stuttgart on Saturday, so the 19-year-old could be given the nod again.
Knauff's fellow teenager Jude Bellingham also found the back of the net at the weekend, and he will be out for some personal revenge after his goal at the Etihad was controversially disallowed for a foul on Ederson.
Man City-linked striker Erling Braut Haaland has now gone six games without scoring for club and country, but he is yet to draw a blank on home soil in the Champions League.
Borussia Dortmund possible starting lineup:
Hitz; Meunier, Akanji, Hummels, Guerreiro; Can, Bellingham, Dahoud; Knauff, Haaland, Reus