Off the back of his Melbourne derby heroics, Mata notched an assist in Victory's 1-1 draw with Adelaide on Friday night but was substituted in the 66th minute.
Coach Arthur Diles played down any concerns over the 37-year-old, who has three goals and a league-high 10 assists.
"Juan was sore," Diles said.
"He's carried a knock all week from last week so it was important again that we managed him and did the right thing like we always do about all our players. Their health and well-being always comes first.
"And in the end, we've got enough players on that pitch with quality at the end of the match to keep going and get a result."
When asked if there were any concerns over Mata's fitness for Saturday's blockbuster, Diles said: "No concerns for next week.
"We don't want it to be a concern for next week so sometimes we've gotta be on the cautious side."
But fringe Socceroo Genreau hobbled off in the 55th minute and could be in doubt.
"He's just felt something in his quad," Diles said.
"So we'll get him checked out tomorrow. Didn't want to keep him on longer because you don't want to put him at further risk.
"We'll see tomorrow how he backs up and we'll get scans on him and see - hopefully it's nothing."
Diles rotated his entire attack in the second half of Friday night's match, which came off a six-day turnaround from Victory's Melbourne derby win.
"It was important that we'd see how the players would react and respond physically and there was some tired bodies out there," he said.
"A couple of the subs were probably forced with minor little injuries, and one or two to avoid injury."
Saturday's high-stakes clash with fourth-placed Sydney at Allianz Stadium, fifth-placed Victory's third consecutive game against a major rival, could be pivotal in the finals race.
Diles believes the tough games will have his charges "match-hardened" for a potential finals campaign.
"It's a big challenge in front of us," Diles said.
"We've got a nice eight-day turnaround now so there's gonna be a few bruised and battered bodies there that need those extra couple days to recover which is timely for us.
"We'll do everything we can and make sure we do everything correct next week that we turn up for another derby. It's our third one in a row and it's also a privilege that you play in these matches. We've got to be ready for that."
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