Rodriguez lost seven minutes and 43 seconds to stage winner and overall race leader Michael Matthews (Orica-GreenEdge) and rival Cadel Evans (BMC) on the stage, dashing any hopes of taking the race victory.
The Katusha leader suffered from deep cuts, fractured rib and a broken thumb as a swath of the peloton was brought down on slick roads within the final 12km to Montecassino.
"It hurts to leave the Giro, but there is no other option," Rodriguez said in a team statement. "The crashes were bad for all of us. The road was very slippery and we were going 60km an hour. Just touching your brakes was enough to crash. But that is a risk we always take. It is part of our job to try to be in the front to fight for the victory.
"I really cannot blame the organization or the local roads. After the crash I got back on my bike immediately, more full of aggression and determination, but after a while I clearly felt what the problem was, as I could not breath anymore."
In addition to Rodriguez, Katusha's Giampaolo Caruso and Angel Vicioso were also forced to abandon after crashing in today's stage. Caruso was already carrying a scaphoid fracture from crashing in Belfast during the race's depart in Ireland.
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