Joe Marler is expected to be fit to play for England in their opening RBS Six Nations game against France at Twickenham on Saturday (February 4th), despite breaking his leg earlier this month.
The Harlequins forward has made a rapid recovery from the fracture, which was sustained in a Premiership game on January 10th.
Speaking to BBC Radio 5 live, forwards coach Steve Borthwick said: "Everything is on track for Joe. To have him back fit is brilliant. He's been incredibly diligent to make sure he is in the best physical shape."
A further boost has come with the news that flanker James Haskell is also fit again, and with Chris Robshaw injured the most likely switch in the formation will be to move Maro Itoje from the second row to the back row.
"The way he plays, it's not about trying to change anything. It's about going on the field and bringing energy, enthusiasm and physicality," Borthwick said of Itoje.
England will be the favourites going into the tournament, but Ireland's recent eye-catching form - they beat both New Zealand and Australia in the autumn - and the fact that England must face them in Dublin means the men in green will be the team most likely to stop the winning machine that Eddie Jones has assembled.
However, France are always keen to spring a surprise, Wales will also hope to challenge strongly and both Italy and Scotland - who visit Twickenham on February 26th and March 11th respectively - will be keen to show they have improved and are not just making up the numbers.
Italy's performances have been criticised in some quarters and there have been calls for a relegation system to give other European countries like Georgia and Romania a chance to play the top northern hemisphere sides.
However, Six Nations chief executive John Feehan said this idea is not on the table. Speaking to BBC Wales, he said: "We think they [Italy] have been a good addition to the Championship since they have entered.
"They have improved dramatically but other teams have improved dramatically - it's a relative thing.
"It's not that long ago they beat South Africa in the autumn series so they are capable of beating anyone on their day and worthy participants."
He added that since joining the tournament in 2000 they have won matches against all the other teams except England.
Mr Feehan also discussed the introduction of bonus points, noting that this move has been resisted in the past because of the "inherently unfair" structure of the tournament that means some teams will play three out of five matches at home, while others only play two.
Against that, he noted, there is the desire to encourage teams to score more tries, citing the 27 scored on the final day of the championship two years ago - a day when four different sides had a chance going into the final round of matches - as evidence that teams "can score tries when they wish to and need to".
As well as their three games at Twickenham, England will also play Wales in Cardiff on February 11th, while the crunch game in Dublin will take place on March 18th.