Sam Underhill will have to wait for England call-up
Eddie Jones is to omit Sam Underhill from England's squad for their Grand Slam defence in the belief he has yet to prove himself.
Jones' back-row options have been depleted by injuries to Chris Robshaw and Billy Vunipola, while James Haskell's comeback from foot surgery was aborted after 35 seconds due to concussion.
A possible reinforcement is 20-year-old Underhill, a flanker of rich potential who is being mentored by World Cup winner Richard Hill but has made only 24 appearances for the Ospreys.
While Jones insists Underhill's forthcoming move to Bath means he can be picked by England - Twickenham allows the selection of players based outside of the Aviva Premiership only in exceptional circumstances - he believes this RBS 6 Nations has arrived too early in his career.
"Sam is available now - he wants to play for an English club and has signed for one," Jones said.
"If we wanted to force the issue we could, but at this stage we'll probably look at considering him for the summer tour to Argentina because he hasn't done enough."
Jones will keep faith with the players who completed an unbeaten 2016 consisting of 13 successive Test wins when he names his 34-man squad for the Championship on Friday morning.
Ellis Genge could be drafted in to add cover at loosehead prop, but with Jones insistent that Joe Marler might yet be fit for the opener against France on February 4, the Leicester front-rower may not be needed.
"You're always looking for extra talent, new talent," Jones said.
"I was out in Argentina last week. I came back in Sunday morning and watched 11 games, trying to catch up with where each player is. I'm always looking for that X-factor player.
"There's a couple of young guys coming through, whether they'll be right for this Six Nations I don't know, but there some good young players out there."
The succession planning at full-back has already begun with Elliot Daly and Anthony Watson the alternatives to Mike Brown, who remains first choice but will be 34 by the time the next World Cup begins.
Uncapped Saracens playmaker Alex Lozowski is also a possibility with Jones believing he should not be confined to fly-half.
"I want to have options to Mike Brown. I see Elliot as being a major option and Anthony Watson as being a major option," Jones said.
"We'll run those guys at training to give them experience them and see how they come up.
"Mike is still our first choice and as long as he is first choice he will be selected, but at the same time we are always looking at Plan B and Plan C and Elliot and Anthony are definitely Plan B and Plan C in that area.
"I think Alex Lozowski is a good young player too. Maybe 10 isn't his best position. Maybe 12 or 15 could be his best position because he is such a good rugby player.
"We were delighted to pick him in the squad earlier this year on the basis of what he had done for Saracens and since then he has continued to develop. He is going to be a bloody useful player for us."