The ex-Brighton & Hove Albion midfielder was absent from the first leg due to a yellow card suspension, as Dortmund were demolished 4-0 by Hansi Flick's side in Catalonia.
However, Gross can now return to anchor the engine room, leaving Marcel Sabitzer and Nico Schlotterbeck as the hosts' only absentees for Tuesday's match; both men are nursing knee injuries.
Kovac opted for a 3-5-2 shape for Saturday's 2-2 Bundesliga draw with Bayern Munich in Der Klassiker, but as his side must go gung-ho on the attacking front if they are to stand a chance of progression, he may revert to a 4-2-3-1 setup.
Gross and Felix Nmecha should act as the double pivot in that scenario, while Karim Adeyemi and Jamie Gittens can feel hopeful of being recalled to the wide areas.
Maximilian Beier was on target in the weekend's derby, but if Kovac does switch to a 4-2-3-1, the German will likely have to accept a cameo role as Julian Brandt plays off of Serhou Guirassy.
Another alteration from Der Klassiker ought to see Ramy Bensebaini return to the left-back role over Daniel Svensson, while Niklas Sule should be the one to make way if Kovac does opt for an additional attacker.
However, Julian Ryerson, Emre Can and Waldemar Anton - who netted the equaliser on Saturday - are set to reprise their roles, as is first-choice goalkeeper Gregor Kobel.
Borussia Dortmund possible starting lineup:
Kobel; Ryerson, Can, Anton, Bensebaini; Gross, Nmecha; Gittens, Brandt, Adeyemi; Guirassy
Written by
Ben Knapton