Harlequins youngsters Kyle Sinckler and Will Collier can solve England's tighthead shortage, according to coach Jon Callard.
Tightheads Sinckler and Collier will battle for the final prop berth for the tour of New Zealand in England XV action against the Barbarians at Twickenham on Sunday.
England entered the RBS 6 Nations with just Bath's Davey Wilson fit and experienced at tighthead, forced to blood Henry Thomas with Dan Cole sidelined through neck trouble.
Sinckler and Collier guided Quins to the Aviva Premiership play-offs, and now Callard believes the fast-developing duo indicate a rapid growth in resources in a previous problem position.
"It is an interesting battle, again they've had the opportunity of tuition last week with the senior coaches where they've been under the watchful eye of Graham Rowntree," said England XV coach Callard.
"He's obviously had an inkling of what he wants to go to New Zealand.
"Hopefully we'll give both a chance in terms of game time; it isn't winner takes all by any stretch of the imagination.
"The senior team will already have a certain eye of what they want in terms of who goes out next week.
"But for us it's about those performing first and foremost for this team, and not worrying what the flight could be like on Monday.
"All that will take care of itself.
"It's a fantastic opportunity for these players, right across the board."
Saturday's Premiership final has robbed England of as many as 15 Saracens and Northampton stars for the first Test against New Zealand in Auckland on June 7.
The league finalists will join the tour on Monday, along with anyone who impresses against the Barbarians this weekend.
Head coach Lancaster has said one of Sinckler and Collier will join England's tour, with both capping fine breakthrough campaigns.
Harlequins will boast four front-rowers in New Zealand and six across England's two summer squads, leaving Callard hailing The Stoop club's commitment to home grown talent.
Callard praised O'Shea for promoting Sinckler and Collier last summer rather than chasing another import when scrum cornerstone James Johnston signed for Saracens.
"Conor has a fantastic coaching team around him, Tony Diprose, John Kingston in particular," said Callard.
"And with the front-row lads coming through, Rob Buchanan and Joe Gray, and Dave Ward has come through and been sensational this year too.
"So a lot of credit to Conor and his coaching team for what they've done there.
"And the proof's in the pudding that they've had a great season.
"I would also give credit to the work that Graham Rowntree has done with Ian Peel, the development scrum guru within the union, who has taken clinics around the country and led techniques.
"They are doing a fantastic job; it's a hugely important part of the game we don't want devalued.
"It's been there for hundreds of years and long may it remain."
Leicester lock Graham Kitchener will captain the England XV that includes three full caps and eight England Saxons stars.
Fiji-born Army solider Semesa Rokoduguni will add flair to a backline marshalled by Exeter inside-back duo and England Under-20s graduates Henry Slade and Sam Hill.
Callard rejected talk the Barbarians contest has been devalued by the fixture clash with the Premiership final and first New Zealand Test.
The former Bath and England full-back said the non-cap Twickenham international helps senior boss Lancaster add vital depth to his wider squad.
"We're getting better across the board, not just at tighthead," he said.
"Generally the depth-chart we're having now is really starting to fill up.
"We're now starting to get a real, strong pool of players, to the point where we could go five or six deep.
"It's vitally important that all these players have a chance to make the New Zealand tour.
"Any one of these players could be on a plane next week."