The 26-year-old has missed the Tigers' last three games through suspension after being dismissed in City's 3-1 defeat to Liverpool.
"We can't have anyone losing the plot," Brown said. "There can be no room for not understanding what's at stake.
"Those with the presence of mind and composure and know how much is at stake will be the ones who are selected.
"It's about calm minds on Sunday, more so than the rest of this season because it's a one-off where if we win the game we're in the Premier League, simple as that."