When asked about his thoughts on the flashpoint, as he announced his Blues side to face the Lions on Wednesday, Umaga gave the media short shrift.
The incident in the 2nd minute of the first Test left Lions captain O'Driscoll with a tour-ending shoulder injury requiring surgery.
"That was 12 years ago, if people can't put it behind them I suppose they never will", Umaga told the Press Association, ahead of the Blues hosting the Lions in Auckland on Wednesday.
All Blacks superstar Sonny Billy Williams has been cleared to start for the Blues after a knee injury, with Umaga naming a strong side for the hotly-anticipated encounter.
Umaga has never gone into any great detail about the incident.More news: Unprecedented rift: Arab states cut relations with Qatar
"It's about this group now and their time against the Lions and the memories they make, hopefully they're positive ones then we move on from there".
However, the 44-year-old was willing to discuss how the Lions may bounce back from their disappointing showing against the largely semi-professional New Zealand Provincial Barbarians on Saturday.
'But that's what happens, especially with a juggernaut like that.
"We've got pretty good coaching staff, and trainers as well - I've worked closely with them", Williams told reporters on Monday.
'They will want a more polished performance but we just have to keep the pressure on them.More news: Pittsburgh Penguins vs. Ottawa Senators 2017
"The key thing for Sonny is he comes with a certain skillset and attributes and we want to see that, as long as it sticks within what we're trying to achieve and the patterns we're trying to play".
'But we've just got to concentrate on ourselves.
"Getting through the field-based footy is easy, (and) I just push back the weights until the break of fast - thank God in New Zealand, in this part of the world, we only fast for nine hours a day, 10 max".
"We felt like it was our responsibility to protect him and the best way to do that was to play well in the second test".
Players returning who missed the win over the Reds in Samoa include All Blacks Charlie Faumuina, Sonny Bill Williams and George Moala along with Maori All Black Ihaia West, Blake Gibson, Augustine Pulu, Matt Duffie and Michael Collins.More news: 'One Love Manchester' concert goes on, drawing some 50000 fans
"If you play well you get remembered and if you don't play well that's remembered, too".
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