Mitchell has suffered major ankle and hamstring injuries in the last two years and returned to action at the end of the Waratahs' Super Rugby campaign.
But the Australia head coach reckon 58-cap Mitchell possesses the experience that could be vital in the championship, which is held less than a year ahead of the 2013 Lions tour.
"I guess Robbie looks at me as I've got some history with this group and my history goes for a number of years now," said Mitchell.
"I don't want to rely on that history, now that I'm here in this squad I want to challenge the guys who are in the spots ahead of me and hopefully push for a spot at some point."
Mitchell admits the past two years have been hugely frustrating and have taken a mental toll but he is confident in his current fitness.
"Mentally has probably been the toughest challenge," said Mitchell.
"It's just about seeking motivation when the light at the end of the tunnel is so far away and when you have set-back after set-back.
"It's important just to surround yourself with pretty positive people, but also understand that you're going to have your darker times as well as your positive ones."
And the jet-heeled wing is not with content with just making the squad. There is fierce competition in the Wallabies backline but he is determined to make the starting team.
"By getting here we now have the pressure to go out there and perform and if you don't there are any number of capable blokes to stand up and take that role from you."