Porte opens up about Sky departure

Richie Porte has opened up about his decision to leave Team Sky for greener pastures elsewhere, but maintains he's still Chris Froome's number one guy for the rest of this Tour de France.

Australian star Richie Porte has confirmed he will leave Team Sky at the end of the season. (AAP) Source: AAP

The Tasmanian, who confirmed he is leaving Team Sky at the end of the year live on SBS after the the Stage 9 team time trial, laid out his reasoning in more detail during the Tour's first rest day.

"At 30 years of age, I feel I am at the optimal period of my career and I really want to make a fist of leading a team regularly," he told Fairfax Media.

"So I need to make the leap of faith and find out for myself if I am capable of it, which I believe I am. But the rider I am in the future will always be a by-product of four years of development at Team Sky."

Porte maintained that he would give his all in support of team-mate Chris Froome's tilt for a second Tour victory, which is so far going to plan. Froome currently holds the maillot jaune, albeit by a slim margin from BMC Racing's Tejay Van Garderen.

"I'm here with Team Sky; I'm wearing the Sky kit. I love this team," Porte told assembled media during the rest day.

"Froomey is one of my closest friends and so are the rest of the guys. I know what my job is here and I'm excited now to get into the mountains. If you're talking about (Nairo) Quintana and all these other guys, (Vincenzo) Nibali, I can't wait to chase them.

"That's my job and, if they attack, I'm going to chase them for my mate Froomey. I'm looking forward to it."