Gerrans finished three seconds in front of Spaniard Egoi Martinez on the 183-kilometer (114-mile) run from Embrun, France, to Prato Nevoso, Italy. American Danny Pate placed third, 10 seconds behind the leader.
Schleck's ninth-place finish was good enough to take the race's yellow jersey from Cadel Evans of Australia, who slipped to third place overall.
Schleck led Austrian Bernhard Kohl by seven seconds and Evans by eight seconds heading into Stage 16, which will be run Tuesday after a day of rest for the riders.
Notable deaths of 2014 [PHOTOS]
Michael Sam cut from the Dallas Cowboys