The Marlins placed Snelling on the 15-day injured list Wednesday with a left elbow UCL sprain.
It's a brutal blow for the Marlins and for Snelling, who just made his major-league debut last week. Whether the rookie southpaw undergoes season-ending surgery hasn't been determined yet, but it's a distinct possibility given the nature of his injury. Braxton Garrett is set to enter the Marlins' rotation in Snelling's place.