Spurs striker, Bethany England, is also sidelined due to injury and has been replaced by Jess Park from Manchester City.
Walsh and England are the only players missing from the Lionesses squad that reached the Women’s World Cup final.
Sarina Wiegman’s 24-player squad includes recalls for Lucy Staniforth and Maya le Tissier.
Aston Villa midfielder, Staniforth, and Manchester United defender, Le Tissier, both served as reserves for Australia before the World Cup.
England, aged 29, underwent hip surgery on September 6th and will miss the start of the Women’s Super League season.
Barcelona midfielder, Walsh, aged 26, suffered a knee injury during the World Cup, but Wiegman stated that it has “nothing to do” with her current ailment – a new calf injury that will keep her out this time.
“[Walsh] has a minor calf injury, and the recovery time is too short for her to join the team. It’s not a major issue, but she’s not ready to play,” said Wiegman.
Chelsea’s Fran Kirby and Arsenal’s Beth Mead missed the World Cup due to long-term injuries, but Wiegman mentioned that this camp came too soon for their return to the squad.
“Beth [Mead] needs to take further steps to get playing time and consistency. Fran [Kirby] is very close,” added Wiegman.
“[Kirby] has played some pre-season friendlies and performed well. Again, it’s a bit too early. I’m really looking forward to seeing them play.
“They were strong supporters of the team over the summer. They were two of the biggest fans. It’s disappointing because they are mentally ready, but it just requires a bit of patience.”
The Lionesses will face Scotland on Friday, September 22nd in Sunderland before traveling to Utrecht to take on the Netherlands on Tuesday, September 26th.
England also plays Belgium in their Nations League group, and the winner will qualify for the semi-finals in February.
“International windows are always competitive. We always play to win, but sometimes we make choices for development,” said Wiegman.
“But that’s not the case now because we want to win the Nations League to qualify for the Olympics.”
Wiegman is ‘very worried’ about the international calendar
The inaugural Women’s Nations League competition comes within a month of the World Cup final in Sydney and just before the WSL season kicks off on October 1st.
Wiegman said she was “very worried” about the short turnaround for international players and has once again urged global football federations to look at the jam-packed calendar.
“I was worried before the World Cup, and we knew it was a short turnaround. We really have to get connected with Fifa and Uefa to make that better,” she added.
“The game is growing, which is really good, but it has to grow together, and players need some rest too. Next week they come in, and some players only had six days off, which, after such a high-pressure competition, is not good for them.
“We have major tournaments in the summer all the time. The urgency to solve it and make it better is really high. We first have to see how they are physically and get them fresh. That’s going to be a challenge.”
An ongoing dispute between the Lionesses and the Football Association over performance-related bonuses will be readdressed when the squad meets up next week.
Wiegman said she is “positive” an agreement will be reached between both parties.
“The players agreed to disagree before the [World Cup] tournament,” she added. “It’s been such a short turnaround, so those conversations will start again. I’m very positive they will have a good outcome.
“I’m very hopeful, I’m very positive. The environment has been really good. It just needs a little more time to get some good solutions.”
What is the new Women’s Nations League format?
World Cup runners-up England are in League A of the Nations League, which has four groups.
The teams play each other home and away, with the standings at the end of the group stage determining promotion and relegation between the leagues, as well as qualification for the finals.
The four group winners in League A meet in the semi-finals, with the two finalists joining hosts France as the European representatives in the Paris 2024 Olympic Games.
The Nations League will also affect qualification for Euro 2025, which will be held in Switzerland.
England are the nominated nation to secure qualification for the Olympics on behalf of Team GB, but they could be held back in their group by Scotland, who have a chance to take points off their rivals and spoil their Paris dream.
Full England squad
Goalkeepers: Mary Earps (Manchester United), Hannah Hampton (Chelsea), Ellie Roebuck (Manchester City)
Defenders: Millie Bright (Chelsea), Lucy Bronze (Barcelona), Jess Carter (Chelsea), Niamh Charles (Chelsea), Alex Greenwood (Manchester City), Maya Le Tissier (Manchester United), Esme Morgan (Manchester City), Lotte Wubben-Moy (Arsenal)
Midfielders: Laura Coombs (Manchester City), Jordan Nobbs (Aston Villa), Jess Park (Manchester City), Lucy Staniforth (Aston Villa), Georgia Stanway (Bayern Munich), Ella Toone (Manchester United), Katie Zelem (Manchester United)
Forwards: Rachel Daly (Aston Villa), Lauren Hemp (Manchester City), Lauren James (Chelsea), Chloe Kelly (Manchester City), Alessia Russo (Arsenal), Katie Robinson (Brighton)