England must improve their discipline given they are the second-best side in the world when they have 15 players on the pitch, says Rugby Football Union chief executive Bill Sweeney.
During a miserable Six Nations campaign, England received eight yellow cards and one red across five matches, meaning they played 118 minutes - almost a game and a half of rugby - at less than a full complement.
They finished the 45-21 defeat by South Africa in July with 13 men after yellow cards for Tommy Freeman and Guy Pepper, while four second-half sin-binnings contributed to Argentina coming close to a successful fightback a fortnight later.
"It has been a big internal discussion," said Sweeney, who claims analysis also shows England slip to eighth or ninth best in the world when they are down to 14 players.
"[Head coach] Steve [Borthwick]'s very conscious of that and he's working really hard with the players to improve that aspect.
"You need all your players on the pitch for as long as possible. That's something we need to address."
England face Australia on Sunday in the first match of their November campaign.
Borthwick's side comfortably won last autumn's meeting between the two teams, but the Wallabies' shock 42-37 victory in 2024 is a recent reminder of their quality.
After matches against Japan (14 November) and New Zealand (21 November), England will play another southern hemisphere opponent in the first Nations Championship finals weekend at Allianz Stadium, Twickenham.
The new biennial event, introduced to bring a clearer narrative to the Test calendar outside of Rugby World Cup and British and Irish Lions tour years, culminates in six play-off matches over three days.
The teams at the top of the northern and southern hemisphere standings will play off for the Nations Championship title, while all matches count towards a Ryder Cup-style Hemisphere Shield trophy.
Sweeney admitted ticket sales for Friday's fixtures - which will see the sixth-placed and third-placed teams in their respective standings face off at 16:40 and 20:10 GMT respectively - had been "challenging" as the new tournament attempts to fill an 82,000-seater venue.
The upper tier of Allianz Stadium has yet to be opened, with plenty of seats still available in the lower section.
The identity of the teams involved in Friday's play-offs will only be finalised after the previous weekend's action.
With three of six rounds played, the current standings would pit Italy against Fiji in the day's first game, and England against Australia in its headline fixture.
"It's uncharted waters," Sweeney told BBC Sport of the finals weekend.
"Saturday and Sunday ticket sales are going well - Friday's a challenge at the moment.
"We're waiting to see how things go after this weekend when things start to firm up a bit and you'll get a better idea of where the league rankings are.
"A lot of fans still don't fully understand what it is and we've done a fair bit of education, but maybe not enough.
"Friday does remain a challenge, but we're confident that we'll see an uptick in ticket sales."
The organisers of the tournament, which is a joint venture between the Six Nations and Rugby Championship organisers Sanzaar, will hope to avoid a backdrop of empty seats for the start of their new showpiece.
They have already had to negotiate a change of plan for the second edition of the Nations Championship.
A provisional schedule had been mapped out with Qatar hosting a lucrative finals weekend in 2028, before the event was transplanted to the USA in 2030 to drive interest in the sport in the country which hosts the 2031 Rugby World Cup.
However, the US-Israel war with Iran, and the broader instability that has caused in the Middle East, has brought alternative arrangements to the fore - with Spain, keen to prove itself having bid for the 2035 Rugby World Cup, a possible host for 2028.
"There's a conversation between wanting the most commercial return or wanting to develop the tournament and have greater accessibility for the fans," said Sweeney.
"It could be that a return to London is the best thing in the interest of the competition. It could be that you go to France and host it there.
"It could be you go to Spain or it could be Middle Eastern interest is still there and they'd want to host it somewhere else."
Six Nations and Sanzaar decided at a recent meeting in Sydney to set up a dedicated team to focus full-time on running the Nations Championship and accelerate the event's development.
England v Australia
Nations Championship
Sunday 8 November, 15:10 GMT
Allianz Stadium, Twickenham
Live commentary on BBC Sports Extra, BBC Sport website and app
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