Lancaster insists the make-up of his starting XV will be determined as much by what happens on the practice field as how a player performs on the pitch.
A committed 13-6 RBS 6 Nations victory over Scotland on Saturday launched what has been billed as an exciting new era for English rugby on a triumphant note, but it was an unconvincing performance.
Fringe players hoping to force themselves into contention for Saturday's trip to Rome will be given the chance to stake their claim during a full-blooded session staged on Tuesday.
"You make training competitive and that's one of the things I've tried to do, certainly over the last two weeks," said Lancaster.
"For example when we do 15 v 15 tomorrow, I'll try to make it so that the players who are on the fringes or are on the bench get a genuine opportunity to play.
"The session will be competitive, allowing the players to show their skills rather than just give them a bib and tell them to be a defender.
"It's when you get that competition and desire for the shirt that you really start to get high performances.
"Everyone has to train well. I place as much importance on how players conduct themselves in training during the week as on what they do at the weekend.
"I want to create a mindset where people are thinking about being excellent every day because that's what it takes to keep or gain the shirt."
England will train at the football academy by the O2 Arena on Tuesday if the pitch at their Pennyhill Park base fails to defrost.
One of those hoping to make his mark in the session will be number eight Ben Morgan, the Scarlet who made his Test debut at Murrayfield as a second-half replacement for Phil Dowson.
Morgan, 22, impressed during his cameo and Lancaster hinted that he could be one of the players who is under consideration for a starting place.
"Part of the selection discussion over the two weeks has been about the back row," he said.
"I was pleased with its balance on Saturday and I thought Tom Croft, Chris Robshaw and Phil all contributed in different areas.
"We were pleased with Ben Morgan's impact from the bench. He has taken a huge step to go from no representative rugby straight into the England side.
"For him to come here and be involved as he has been, he is clearly finding his feet quickly.
"We are pleased with the impact he made but we also bear in mind the steps he has taken.
"It is part of the selection dynamic for this weekend."
Toby Flood made a second-half appearance for Leicester against Newcastle on Saturday in his first appearance since damaging knee ligaments on New Year's Day.
However, Lancaster stated Flood's lack of game time all but rules him out of contention against Italy on Saturday.
Scrum-half Lee Dickson could yet participate at the Stadio Olimpico despite breaking a bone in his left hand against Scotland.
"Lee saw a specialist last night and we're very optimistic of his chances of being available this weekend," said Lancaster.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.