Sam Underhill is now a major doubt to play any part in the Six Nations, with Bath confirming that the England flanker requires surgery on his ankle.

Underhill picked up the injury against Northampton Saints last Sunday, finishing the match after coming off the bench. Johann van Graan, Bath’s head of rugby, revealed earlier this week that Underhill had picked up a knock to his ankle while setting up a try for Max Ojomoh. “After the game it was quite sore and that is a worry for him,” Van Graan said on Wednesday.

In their team announcement ahead of facing Clermont in the Champions Cup this Sunday, Bath confirmed that Underhill will now need an operation.

“Sam Underhill will undergo surgery to rectify a new ankle injury. There is no set timeframe on his recovery,” the club announced.

Underhill injured the same ankle while scoring a try for England against Japan in November, before missing almost a month of action until returning against Newcastle Falcons just before Christmas.

He underwent surgery on his other ankle after England’s summer tour of Japan and New Zealand last year, meaning a total of three ankle injuries in the space of seven months. Another ankle injury at the end of 2018 led to Underhill missing the 2019 Six Nations following surgery.

Underhill’s injury is another blow for England head coach Steve Borthwick ahead of the Six Nations, with full-back George Furbank (arm) and wing Immanuel Feyi-Waboso (shoulder) set to miss the tournament.

Underhill started England’s first eight Tests last year before surprisingly not being given an enhanced Elite Player Squad deal in October. He was then not selected for England’s first two Tests of the autumn against New Zealand and Australia, before returning for the games against South Africa and Japan.

Bath’s back row resources have been hit hard after the game at Northampton, with Jaco Coetzee recovering from a concussion

Analysis: Why coach must select Chessum, Curry and Willis

There must be a parallel universe where a healthy Sam Underhill not only has closer to 80 caps, rather than his current tally of 40, but might also be England captain. A conversation five years ago while England were still reeling from their Rugby World Cup final defeat against South Africa remains one of the most impressive interviews with a young player that I can remember, given Underhill was 23 at the time.

That there is no public timeline for Underhill’s latest injury recovery is mildly concerning because Bath need him for their title charge. England, on the other hand, will now have to do without a player who started 10 of their 12 Tests last year.

Steve Borthwick has great depth in the back row but still needs to settle on a combination for the next few weeks, after England lacked carrying power and muscle in their mauls and line-outs during the autumn. Two players who were not involved for those Tests against New Zealand, Australia, South Africa and Japan but are now right in the mix for selection are Ollie Chessum and Tom Willis.

Chessum is days away from a return for Leicester Tigers after missing the autumn because of a knee issue, with Michael Cheika, the Leicester head coach, suggesting that Chessum could miss England’s upcoming training camp in Girona to get more minutes on the field heading into the Six Nations opener against Ireland. Chessum has not played since the end of October and is not involved for Leicester this weekend against Ulster, with next weekend’s Champions Cup fixture away at Toulouse potentially marking his return to action – a nice way to ease back in after three months out.

England need Chessum’s heft in the maul, scrum and breakdown to get quick ball, and have often looked sharpest when they have been able to field Chessum at six with Maro Itoje and Chessum’s Leicester team-mate George Martin in the second row, as was the case against Ireland and France in last year’s Six Nations.

Meanwhile, if England truly want to add in an effective ball-carrier, then on form they have to go with Tom Willis, who was excellent recently against a large Bulls pack and in last weekend’s win over Bristol Bears, scoring two tries. He can get England over the gain-line and comes up with plenty of defensive turnovers, much like his brother, Jack. Willis was notably at England’s alignment camp on Monday, having not been involved in the squad for the autumn.

Which leaves one spot at open-side flanker. Ben Earl was England’s highlight of the Rugby World Cup and had a strong Six Nations at No 8, before dipping slightly in the autumn, when his work rate remained high but his carries were less effective and he committed high-profile mistakes (a no-arms tackle against New Zealand, missing a key tackle on Damian de Allende against South Africa). He has been England’s No 8 dating back to the Fiji warm-up game before the World Cup, and could easily shift back to seven despite starting England’s last 16 Tests at the back of the scrum. Yet bringing Earl off the bench to pick on tired defences, while giving Willis licence to empty the tank inside 50 to 60 minutes, makes for a promising prospect.

That would leave the No 7 shirt open for Tom Curry, who remains one of England’s fringe world-class players and a key leader in Borthwick’s pack. With Chessum clearing rucks while improving the line-out and Willis charged with carrying deep into double figures, Curry would be freed up to go hunting for turnovers and to lead England’s tackle count.

There is a nice balance there. Underhill, if fit, might have even started at openside flanker. Without him, England still have a number of high-quality options.