England forwards coach Steve Borthwick says Mako Vunipola's return to the side is a "great boost" and has warned oppositions that the prop may be better than ever.
Vunipola is expected to feature against Ireland on Saturday at Twickenham, live on Sky Sports Action, after recovering from a hamstring problem.
The Saracens loosehead prop was injured just half an hour into the Champions Cup final against Leinster in May before undergoing surgery, but he was named in Eddie Jones' 31-man squad for the Rugby World Cup.
"To have a player of his calibre close to being on the pitch is clearly a great boost and I am very pleased for him", said Borthwick.
"It is a testament to his hard work and how well our strength and conditioning and medical departments have worked together to get him into the shape he is. We are very fortunate to have three very good players in that position.
"When you have had long-term injuries and you are not with the team it is challenging. It is also a time when you can develop and improve in areas that were deficient in the past. Nobody wants to be injured but it gives an opportunity to come back as an even better player."
England also remain hopeful that back-row trio Mark Wilson, Tom Curry and Sam Underhill will all be fit to face Ireland.
Wilson has been carrying a rib complaint, Curry a shoulder concern and Underhill an ankle problem, but all three "trained well" on Wednesday and will be monitored throughout the week, according to Borthwick.
England face Ireland in their next Quilter International on Saturday at Twickenham live on Sky Sports Action. They also face Italy (September 6) in Newcastle as part of their Summer Internationals, all on Sky Sports.