His current front-bench is simply not cutting it. National has had a difficult year. But most of that party's problems have been self-inflicted, such as fiddling with teacher-pupil ratios, have flowed from unpopular policies such as asset sales, or have been beyond the party's control, such as donations to John Banks' mayoral campaign.
Labour has caused National few difficulties. It needs to lift its game and put the Government's weaker ministers on notice.
That would be the case for any Opposition party nearing the end of the first year in the three-year electoral cycle. But Shearer needs to get more out of his line-up to make up for his inexperience as Leader of the Opposition.
On top of that, the return to Parliament of Winston Peters and the Greens' adoption of a far more media-focused strategy mean Labour is facing a daily struggle for coverage - and therefore public profile - which was previously the major Opposition party's as of right.
Shearer has made no secret of his intention to review shadow portfolio responsibilities and caucus rankings after his first 12 months as leader. He will probably announce the reshuffle following Labour's annual conference next month, giving allowing those handed new responsibilities time to get up to speed before the first sitting of Parliament next year.
Nanaia Mahuta, Labour's education spokeswoman, is likely to be tipped off the front-bench.
Shearer is known to believe education is a portfolio where Labour should be making all the running and making life intolerable for Hekia Parata, an increasingly accident-prone minister. But Labour isn't.
A big questionmark also hangs over Shane Jones, who has been sidelined for four months while the Auditor-General Lyn Provost investigates his granting of citizenship as a minister in the last Labour Government to a Chinese millionaire despite Internal Affairs advising him against doing so.
Senior whip Chris Hipkins is a strong contender for promotion, and Shearer might be tempted to elevate impressive new MPs such as former party president Andrew Little and Dunedin North's David Clark to Labour's second bench.
Shearer will be conscious that reshuffles create enemies. For that reason alone, David Cunliffe, who Shearer defeated in last December's leadership ballot, will remain on the front bench.
His talent is too valuable to squander. Shifting him would destabilise the Labour caucus and buy a fight the leader does not need.