The great conundrum of English rugby - otherwise known as the red rose midfield - remains unsolved. The national coach has dropped both of his Six Nations centres, Billy Twelvetrees and Luther Burrell, for this weekend's last hurrah against the All Blacks in Hamilton, and if the fresh combination of Kyle Eastmond and Manu Tuilagi click together as readily as they did in Auckland, it will inevitably lead to a major reassessment of the available options.
Twelvetrees, the one truly creative spirit in the back division since the demotion of the Saracens full-back Alex Goode, made several mistakes too many during last week's one-point defeat in the Dunedin test and has paid a heavy price.
He should not be too hard on himself - Lancaster went out of his way yesterday to stress that England had asked an awful lot of a man playing for the first time in six injury-hampered weeks - but this is an alarming development for the Gloucester player all the same.
Burrell, meanwhile, will take little comfort from being named among the replacements.
The Northampton centre missed the Auckland test after arriving late on tour. Along with more than a dozen others, he had Premiership final business to address before flying out.
And while he returned to the starting line-up in Dunedin, he could not reproduce his excellent Six Nations form against the high-calibre New Zealand pairing of Ma'a Nonu and Conrad Smith. As a consequence, he finds himself back where he started last September: that is to say, behind Tuilagi in the pecking order.
"I don't think it's right to suggest that what's happened here has muddied the pool," Lancaster said. "The truth is that we're still finding out who can deliver at the highest level. We've had a good chance to look at Twelvetrees over the course of the season, while Eastmond has had the one opportunity in Auckland. He took that opportunity, so we think now is the right time to give him a second go.
"Billy wasn't that far off in Dunedin - it was a big step for him to play that game, having not had a match since early May - but when I looked back at the two matches, I thought Kyle edged it. Do I regret picking Billy for the second test? No, although it was certainly a tough ask for him. The thing is, we're going to need four centres for the World Cup campaign and we need to find out about people."