Eddie Jones has been told Sam Underhill is unavailable for his debut autumn campaign as England head coach.
Jones stated a fortnight ago he was interested in the eligibility of the uncapped Ospreys flanker for the series against South Africa, Fiji, Argentina and Australia after James Haskell was ruled out for six months by a foot injury.
Jones had identified former England Under-18 captain Underhill as a star of the future and a possible back row option for the autumn, although Nathan Hughes, Jack Clifford and Maro Itoje are more established contenders.
Twickenham's edict on only selecting overseas-based players in exceptional circumstances muddied the waters over his availability, but the new eight-year agreement between the Aviva Premiership clubs and Rugby Football Union has clarified that Underhill can not be involved.
"We discussed it again with Eddie and we agreed with the exceptional circumstances clause and left it where it is," Rugby Football Union chief executive Ian Ritchie said.
"Everybody is clear what it means and Eddie is very good at communicating that to players. We think it is a good clause and the right clause. That is the situation that we will sustain during the agreement."
The 'Professional Game Agreement', which expires in 2024 and is worth over £200million, has provided a definition of 'exceptional circumstances' for the first time.
Under the previous deal it was thought to cover a number of scenarios, but Premiership Rugby Limited chief executive Mark McCafferty insists it covers only one eventuality.
"It's injury related. When we wrote the first agreement it was always injury related, we just never wrote it in as specific as that," McCafferty said.
"It has never really come under pressure, although I know it has been speculated about with one or two players.
"But if the system is working well and there is enough choice, then it doesn't come under pressure.
"We have clarified it only in the sense of writing what we had in mind eight years ago - if you get big injuries ahead of playing a tier one country.
"Maybe the next player in line is inexperienced, almost to the point of there being a safety issue.
"In those circumstances that would definitely be exceptional and you might have to look elsewhere."
Source: PA
