Tuilagi, 23, has not played on the wing since Leicester and England age-groups, making his senior breakthrough in the centres where he has remained ever since.
However, with fellow Lion Billy Twelvetrees back fit and in midfield for the second Test, Lancaster has opted to shift Tuilagi out to the right wing.
But despite starting the match from wider out, Lancaster insists his Samoan-born wrecking-ball has not been marginalised.
"He's [Tuilagi] looking forward to it," said Lancaster.
"We had a long chat with him about it. I sat down and spoke to him a couple of times. He just wanted to be clear in his own mind about the position stuff, particularly the backfield stuff.
"Once he understood that and his role in the team and he ran through it training because we had Monday and Tuesday when we continually played against each other and with 45 players there is plenty of opposition.
"The longer it's gone on the more comfortable he's felt. On the flip side once he saw and everybody saw the potency of our strike players, he's a great team player Manu and he was happy to do what's best for the team."