"Didn't finish on time (way out actually) on Mt.Etna stage," said McEwen via his Twitter feed. "Giro over for me. Haven't felt good at all. Home, recover & rebuild for June."
The pair finished 59:35 down on the time by stage winner, Alberto Contador.
HTC-Highroad's Mark Cavendish was sparred a similar fate, by a margin of just 30 seconds, 33 minutes ahead of the Australians. Cavendish was escorted to the finishline by teammates Alex Rasmussen and Mark Renshaw while Sacha Modolo (Colnago - CSF Inox), Adam Blythe (Omega Pharma-Lotto), Russell Downing (Sky Procycling) and Danilo Napolitano (Acqua & Sapone) were also in the group.
"Well my legs exploded more violently than the f%&king volcano we were racing up today," said Cavendish via his Twitter feed. "Mount Etna. Twice. In 1 stage. Not nice."
Renshaw wasn't impressed either claiming: "That wasn't cycling today, that was going to hell and back... twice."
Two sprint stages remain for Cavendish following Monday's rest day – stage 10 and 12.