Dan Ward-Smith's prolonged battle for a World Cup place could go right to the wire.
The uncapped Bristol number eight is continuing his recovery from a serious knee injury that dashed hopes of an England debut during the RBS 6 Nations Championship earlier this year.
Ward-Smith has travelled to the Algarve as part of England's World Cup training squad, but not been able to take part in full team training.
The players reconvene in Bath next Tuesday, and Ward-Smith might need every minute of rehabilitation available to him before head coach Brian Ashton announces his final 30-man squad on August 14.
Ashton said: "Dan has made a remarkable recovery to get where he is, but he is still just running in straight lines.
"We will just have to wait and see."
Ward-Smith is among several players who have not embarked on full-team training in sweltering temperatures on the Portuguese coast, being joined by the likes of Josh Lewsey (Achilles tendon), Lawrence Dallaglio (knee), Paul Sackey (knee), Shane Geraghty (hamstring), Lewis Moody (Achilles tendon) and Jason Robinson (knee).
Ashton, meanwhile, is leaving no stone unturned in his bid to emulate 2003 World Cup-winning supremo Sir Clive Woodward.
Royal Marines physical training instructor Dave Sylvester has been seconded to England's support staff for the build-up and seven-week competition during September and October, with Ashton also tapping in to the expertise of forensic psychiatrist Dr Steve Peters, who has helped mould Britain's top cyclists into Olympic and World Championship winners.
Recalling three days of training exercises with the Marines in Dorset last week, Ashton said: "To pull players together you need to put them in a very challenging environment where they have to pull together to be successful.
"A lot of it is teamwork and leadership. I wanted them to be in an environment like they will be in the World Cup, which is hostile and uncomfortable. They lived the life of a Royal Marine, effectively, for three days.
"I also wanted to challenge the players against one another, but also individually. At certain times, players were pulled out of their team and given a challenge against another individual from another team.
"The Marines show adaptability under severe pressure. There were physical and mental pressures, and combined tasks of both, so the players had to make big decisions when they were absolutely out on their feet.
"It has accelerated the process of being together as a group. They have bonded together extremely well and, from my point of view, to see players under intense pressure was good. It gave me a massive insight."