Billy Twelvetrees is the pivotal cog in England's all-court attacking threat, according to Ireland assistant coach Les Kiss.
Brian O'Driscoll sat out training on Tuesday suffering the after-effects of a bug, but Kiss expects the 35-year-old to take full part on Thursday to prove full fitness ahead of Saturday's RBS 6 Nations clash at Twickenham as Ireland chase their first Triple Crown since the 2009 Grand Slam.
Fit-again Munster lock Donnacha Ryan has "trained the house down" according to Kiss, and is now in contention for the place on the bench vacated by Dan Tuohy, who broke his arm in the 26-3 victory over Wales.
Defensive specialist Kiss hailed Gloucester centre Twelvetrees' New Zealand-style playmaking role as central to Stuart Lancaster's desire to expand England's attacking repertoire.
"I think he has developed that nice, organised mindset in his game very well," said Kiss.
"He's like a New Zealand second-five eighth, and does facilitate what they are trying to achieve in attack and offers them the ability to go both sides of the ruck, and so do (Jack) Nowell and (Mike) Brown and even (Jonny) May.
"It keeps you alive across the field, and I think Twelvetrees' game is critical for that, because it helps (Owen) Farrell as well."
England boss Lancaster is intent on building a "two-sided attack" to rival world champions New Zealand, who now regularly employ locks as midfield fulcrums in phase play.
Twelvetrees looks to have ousted Saracens' defensive king Brad Barritt as England's frontline 12 as Lancaster aims to build towards Rugby World Cup 2015 and bolster England's front-foot game.
Ireland's Kiwi coach Kiss rates Twelvetrees as England's gateway to their fleet-footed back three of Jonny May, Jack Nowell and Mike Brown, and challenged Ireland to shut off that supply line this weekend.
"They have a really solid, organised approach to their attack," said Kiss. "And that allows the brilliance of some of their individuals to come to the fore.
"Young Jack Nowell for example has been encouraged to throw himself into different moments of the game.
"That may look a little unstructured, but they set that part of it up, even Danny Care having a dart here and there.
"And a lot of their organisation comes through Farrell, orchestrating the shape from 10, to their movement.
"And when you've got guys like Twelvetrees, Brown and May there, they can shift their game when they need to.
"They will eek out or look for the weaknesses and mismatches in your defence, so we just need to have our heads-up this week, that's for sure."
Ryan could now well take a seat on the bench ahead of Ulster's Iain Henderson and Leinster second row Mike McCarthy.
Kiss said the 30-year-old Munster lock's long-term club partnership with Ireland captain Paul O'Connell boosts his chances.
Kiss also backed O'Driscoll to return to full health in time to match George Gregan's world-record caps haul of 139, including British Lions bows, against England.
"Brian has a slight little bug, but he will be fine for Thursday," said Kiss. "We're just managing it now, so we expect him to be fully fine by Thursday.
"He's not feeling the best put it that way.
"Paul (O'Connell)'s actually flying through his markers there, which is a big plus.
"We expect everything to be in a good place.
"It's great to see Donnacha back, he's come back in and trained the house down.
"He's a definite option; we've just got to consider everything, and what our stocks are in that area, but it's certainly timely for him to be back after Dan Tuohy's injury.
"Probably some pluses with Donnacha are that he's worked a lot with Paul in terms of the line-out, and the calling systems are not too far removed in terms of that type of transfer, so that knowledge is a plus.
"In terms of the defensive and attack changes we've made since Joe's come along, he's got to get his head around those pretty quickly, but Donnacha's a smart boy."