With traffic snarled due to road closures related to Sunday's Toronto marathon, Casey got stuck in traffic soon after leaving his midtown home.
More than half an hour into his journey, having failed to make significant progress, he turned his car around and drove home, then took the subway to the downtown arena.
Fellow riders recognized Casey, snapping photos of the coach and posting them to social media. Many also wished him luck in Sunday's decisive game against the Nets.
"I didn't think anybody would recognize me but I guess the shirt gave me away," Casey said, tugging on his black Raptors logo warm-up shirt.
Casey said it's the first time he's used Toronto's subway since last summer.
"It's great, I recommend it to everybody, just not on Game 7," he said.