The Leicester No9 won a Test cap for Britain and Ireland's elite in the win over South Africa on July 4 and has been included in his country's Elite Player Squad for the current season.
But Ellis is currently experiencing problems with an old injury that could force him to miss the games against Australia, Argentina and New Zealand.
The 27-year-old suffered a career-threatening injury in the his club's Guinness Premiership semi-final win over Bristol back in 2007 and spent close to a year on the sidelines.
And although he returned to fitness and played his part for Ian McGeechan's tourists earlier this summer, Ellis is now suffering discomfort in the same knee once more.
"It's really frustrating for me at the minute but I have to get on with it," Ellis, who hasn't played since September 19, told the Leicester Mercury.
"With my sort of knee history, I have to keep on top of it. Without going into too much detail, it is something that will stay with me for the rest of my career.
"I am in the EPS and I always like to put my hand up for selection but, realistically, I need to be playing and I haven't played for the last four or five weeks while other guys have."
And with the likes of Paul Hodgson and Danny Care putting their hands up for selection, scrum-half is not a position in which England team manager Martin Johnson is short of options.
But while Ellis is disappointed that he has not been able to cement his England position since returning from Lions duty, he is far from pessimistic about his current situation.
"I need to make sure that everything is fine," added Ellis.
"I play a lot of rugby and I have to manage it well. I need to make sure everything is in good condition to play rugby and I am just going through a period when I need to top up my rehab.
"I have spoken to other players who have had similar injuries and they say that they have had to keep on top of things too. I am really lucky that I have good medical staff and conditioners around me at the club. They know how to deal with an injury.
"I would never pass up the opportunity to play for England. Hopefully, things will go well in the next few weeks and we will see where we are."