“The Giro has been my main goal this year and I’ve worked incredibly hard all season with this race in mind," Porte told teamsky.com.
“I’ve had a lot of back luck this week with the puncture and the time penalty, but it was the crash on Friday that has taken its toll.
“I fell heavily on my knee and hip which caused me a lot of pain on Saturday’s time trail and yesterday’s stage. I just wanted to keep trying and give it everything but now the medical team have advised me not to continue," he said.
“I'm gutted it’s ended this way and that I can’t stay and support Leo (Konig), Elia (Viviani) and the team in the last week. They’ve been outstanding every step of the way and to not be able to repay that is tough.
Porte will now turn his attention to preparing for the Tour de France where is he is expected to ride in support of 2013 champion Chris Froome.
“The plan for me now is to take some time off the bike, get the medical treatment that I need and reset my goals for the rest of the season and come back fighting. Hopefully I can get myself ready for the Tour team.”