David Wilson will anchor England's scrum for as long as possible against Ireland on Saturday but admits he is unsure of what he can deliver at Twickenham.
A duel with British and Irish Lion Cian Healy, one of the game's most accomplished looseheads, awaits a player who has been limited to just 47 minutes of club rugby in the last two months by a calf injury.
Wilson is being pressed into action after Dan Cole was ruled out of the remainder of the RBS 6 Nations because of a bulging disc in his neck that could yet end his season.
With Henry Thomas deemed unready to start a fixture of such magnitude, it falls to Wilson to complete as lengthy a shift as possible until being relieved by the untested rookie.
Head coach Stuart Lancaster admitted on Monday that England are "not in an ideal situation" and will be delighted if the Bath tighthead survives intact until the final quarter.
Wilson's own outlook on what he can produce is shrouded in uncertainty and he promises only that he will empty the tank in what is a pivotal fixture in the Six Nations title race.
"I think I'm ready to play on Saturday. I would have liked one more game to get my match fitness up, but that's the way it goes," Wilson said.
"I've got no idea how long I can play for. As long as possible I guess - that's what I'm aiming for. I want to do as well as I can for as long as I can.
"Maybe 50 or 60 minutes. If I get through that and perform well, I'll be reasonably happy. I'm obviously eager to make a big impact."
Wilson damaged his calf in a training game before Christmas but having overcome that injury, his return was delayed by a further two weeks because of a tight back.
The 28-year-old finally made his comeback in Bath's 27-23 Aviva Premiership victory at Exeter last Saturday and his lack of match fitness was evident.
"When I initially got the calf injury I thought it would be a few weeks, but I guess I'm not a medic. Maybe that's why I'm not a medic!" he said.
"I was disappointed it took so long. It's frustrating when you're injured and I couldn't do a lot with it being my calf.
"It feels good now and I was well tested in the scrum by Exeter. It was a fast game and the pitch was heavy.
"It was a good workover and I am happy about that. It was a tough test. It might have looked hard and it was.
"I worked pretty hard last week so feel I will be 20 to 30 per cent better this week.
"I'm aiming to do the basics well - scrum well, line-out well, get through that, go for as long as I can and not let anyone down."
The lack of depth at tighthead was exposed as soon as Wilson entered the treatment room, leaving first-choice Cole as the only option in the position amid a clear reluctance from England to field Thomas.
Cole was forced to play longer than Lancaster would have liked against France, finishing the match while Thomas sat unused on the bench, and completed all but five minutes against Scotland.
While Lancaster stressed Cole's workload was not to blame for the bulging disc that has trapped a nerve, the situation has reinforced the need to develop more options in what is a critical position.
"Dan's injury comes with the territory. I've had those problems before, a similar disc bulge but not quite as serious," Wilson said.
"There is pressure on your neck at the scrum and breakdown and even during tackles if you get your head on the wrong side.
"It's an important part of the body. You have to look after your neck and do as much rehab as possible."