Zadkovich strained an ankle ligament in training just over a week ago but coach Branko Culina confirmed he would be fit for the trip to take on the 2nd-placed Roar.
"Ruben seems to have come through OK," Culina told the Newcastle Heral. "He trained really solidly today. He obviously lacks a bit of match fitness, but he's a good enough athlete to handle that.
"We'll see how everyone pulled up after training. The last thing we want is injuries in an already small squad."
Meanwhile, Brockie will come back in after missing the past two A-League matches with injury.
The 23-year old played in both of New Zealand's international friendlies against Honduras, where he set up Chris Wood's first-half goal, and Paraguay this week and will be a welcome addition to the Jets line-up which will be without captain Michael Bridges, defender Nikolai Topor-Stanley and midfielder Jobe Wheelhouse who are all injured.