Gatland could engineer a range of scenarios in his back row, including starting O'Brien and Warburton, but that would mean leaving their best No6 out of the XV.
Blindside Peter O'Mahony and O'Brien were instrumental in disrupting the All Blacks at Aviva Stadium in 2013, a match they had all but won until the clock ticked 80, and were equally effective against the Crusaders in Christchurch.
Warburton' history against New Zealand teams is less gilded.
Captaincy is one of those things that always matters more than it should. To hear Warburton talk of accepting the fact he might not be picked for the test at Eden Park in nine days was curious. Selfless or defeatist? Depends which set of ears you choose to wear, perhaps.
By not selecting Warburton as his starting No7 in the first test, Gatland sends a signal he made a mistake in April. By selecting him, he sends a signal that he is prepared to double down on that error.