Johnson named nine new faces in his party for the quadrangular tournament in South Africa as he looks to kick on from finishing third in this year's RBS 6 Nations.
Lawrie, now 29, is one of those now in line for a senior debut having returned to Edinburgh in 2011 following two years in the English Championship with Doncaster.
And having represented Scotland at U18, U19, U21 and A team level the hooker insists his decision to seek first-team rugby rather than warm the bench was the right call.
"As a front row forward you need to be playing and scrummaging week in week out at the highest level you can," he told the Scotsman.
"So I went down to the Championship with a view to doing that and definitely benefited. You look at guys like Tom Youngs [Leicester and England selected for the British and Irish Lions], who spent time at Nottingham learning his craft, and that's what I had to do, so it was a good opportunity.
"I feel hugely excited at the opportunity I've been given, but I'm a huge believer that it's not the opportunity that counts but what you do with it.
"I'm 29 years old now and I am not going to South Africa just to learn about what's going on. I want to play. That [taking the jersey from Ross Ford] is what it's all about for me."