The European champions need just a point in Tuesday's final Group D match against China in Adelaide to confirm their place in the knockout rounds in Australia and New Zealand.
Wiegman confirmed that Walsh will miss the match after hurting her knee in the win over Denmark but would not be drawn on the key midfielder's prospects at the tournament beyond that.
Even though a point will be enough to qualify, Wiegman wants to go for the win and knows her players cannot afford to dwell on the absence of the influential Barcelona player.
"I think we have a strong enough team," Wiegman, who masterminded England's triumph at the European Championship last year, said on the eve of the game.
"We have a group of 23, so now we have 22, and we have found solutions and we will show that tomorrow.
"It's not nice to lose players - first of all for them and second for the team," she added.
"You have to move on and adapt to a new situation and find a way."
Walsh went down in agony in the first half against Denmark on Friday and was stretchered off in tears with what looked like a serious knee problem.
There were fears that she had joined the growing list of women's players to have sustained a serious anterior cruciate ligament injury.
England are already missing star striker Beth Mead and defender Leah Williamson, their captain, as both recover from ruptured ACLs.
But England subsequently said Walsh had not suffered an ACL injury and would remain with the squad, without saying when she would be back in action.
Tuesday's opponents China are Asian champions and looking to reach the last 16 themselves.
"They are very well organised, they can play a possession game but they can also play a direct style," Wiegman said.
England are among the favourites to win the World Cup and started with an unconvincing 1-0 win over debutants Haiti, before a better performance in beating Denmark by the same scoreline.
