It may yet flag the most significant reorientation of Labour thinking since the party kissed goodbye to Sir Roger Douglas.
So far, Shearer has given little away. But there was a hint yesterday in his remarks about welfare reform that he is planning to shift Labour's stance quite radically in a number of policy areas.
His priority must be getting the speech - it is the first in a series over following weeks - right in terms of effectively communicating what a Shearer-led Labour Party stands for.
Without clarity on the latter, Labour's arrows will continue to bounce off National without doing any harm.
However, refreshing the Labour vision takes time. And time is one comparative luxury Shearer does have.
His critics are guilty of the politics of instant gratification. It is ridiculous to expect a party which has just suffered one of the biggest drubbings in its 95-year history to now suddenly have all the answers.
After being elected leader in December, Shearer made it clear he was not going to rush things. He also knows his relative inexperience in national politics means it is likely he will make mistakes - and that a major one early on could blight his leadership.
The resulting caution has been evident in his stance on the industrial dispute at Ports of Auckland. He was criticised from the left for blatant fence-sitting on what might seem a black-and-white issue for Labour.
But Shearer is simply not prepared to box himself into a corner. That was the mistake Phil Goff-led Labour made a number of times.
Shearer seems determined not to be forced to take positions simply to satisfy traditional Labour constituencies, but which are out of step (or out of touch) with what the great bulk of voters think.
Lastly, and perhaps most significantly, Shearer is going to be a very different kind of leader from his predecessor. Phil Goff was 100 per cent undiluted politician - one of the reasons why voters did not warm to him.
In bucking convention - by not delivering a traditional state of the nation address last month, for example - Shearer is refusing to be pigeonholed.
He is seeking to retain one of his biggest pluses - that voters respond favourably to him as a not-so-obvious politician in much the same way as they do to John Key.
The biggest risk for Shearer now is that next month's speech fails to live up to its billing.
A fizzer would be post-facto justification for the current wailing from the sidelines. But Shearer does not need to be told that.