England are considering whether to fast track Mako Vunipola into their starting line-up for Saturday's pivotal clash with Argentina.
Vunipola has completed only 17 minutes in four-and-a-half months since damaging his hamstring on Saracens duty on May 11 after being forced to abort his comeback against Ireland in August.
The 28-year-old watched as Joe Marler and Ellis Genge made an impression at loosehead prop in his absence but now that he has returned to training he is hoping for an immediate return to the front row against Argentina.
"Sometimes you're better off starting with the adrenaline pumping rather than sitting on the bench," said scrum coach Neil Hatley.
"We'll know more Tuesday or Wednesday where Mako is. We will see in training. He needs to be the best version of himself and we know what he is capable of.
"He is a 50-cap plus player and we know what he brings as a ball carrier and the influence he has defensively on the team.
"But Joe Marler and Ellis Genge have been going exceptionally well and we want that competition within the team to create pressure on the players to work harder and produce more.
"What we produce on the weekend will be a product of what we do in training and Mako is going to have to work hard."
Marler has acted as England's senior loosehead in the absence of Vunipola.
"There are three guys going for two shirts, so that doesn't work. It's great to have Mako back and he's been in training for the last couple of weeks anyway," Marler said.
"He's back fully fit and he brings world class experience and talent into that role. So...I've enjoyed my time!
"I'm determined to give as much as I can to this group to help us win the game on Saturday."
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