The outfielder, who impressed during Spring Training, will not be ready for Double-A Jacksonville's Opening Day.
"We did find out that Marisnick broke his hand," manager Mike Redmond said. "He has a break in his hand, so he's going to be out for a while. Disappointing."
Marisnick was injured against the Cardinals on Wednesday when he was plunked by a Trevor Rosenthal fastball on the left hand. An X-ray that day came back negative.
Marisnick has not seen game action since. On Monday, with the hand still swollen and sore, he saw the doctor again for a second X-ray.
The result showed the break.
The Marlins acquired Marisnick from the Blue Jays as part of their blockbuster 12-player trade in November. He was 5-for-11 in eight Grapefruit League games.
Even before the break, the organization's plans were to start him off at Jacksonville, where he is expected to play center field along side left fielder Christian Yelich and right fielder Marcell Ozuna.
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter