Walsh injured her knee against Denmark on July 28 and left the field on a stretcher, with many fearing her tournament was over.
The midfielder, however, has recovered and she took part in full training with the rest of the Lionesses on Sunday.
Walsh has travelled to Brisbane for England’s clash with Nigeria and Wiegman will make a late call as to whether she plays.
“She’s doing well,” said Wiegman. “She started her rehab straight after we knew what was going on. I can only say it was not a ligament injury.
“She has been on the pitch, training today and now we will wait to see how she recovers and if she does well then she will be available for tomorrow.
“It was a very hard moment and not nice to see [Walsh being carried off on a stretcher against Denmark].
“After the assessment when we know what was going on we said don’t take any assumptions and wait until a proper assessment has been done. That’s what we did then we got the green light to get the rehab started.
“Of course we want every player to be fit and available. Keira wasn’t available for the last match and we know what options we have in that position.
“Katie [Zelem] did really well against China and now Keira is back so that’s really nice for the team too.
“We know we have other options too. Keira is exceptional but other players can solve that, that’s what we’ve shown.”
Walsh missed England’s final group game against China on Tuesday and the Lionesses switched to a back-three as a result.
The 3-4-1-2 formation proved a big success, with England scoring six goals and conceding just once.
And Wiegman has not ruled out playing that formation again, even though the Lionesses have preferred a 4-2-3-1 setup when Walsh has been fit.
“We have two options now – the way we have played and what we did against China, so we will take that into consideration,” she said. “You will see tomorrow what we will do.”
England are clear favourites for their game against Nigeria, with the Super Falcons ranked 40th in the world.
But asked about any fears of complacency creeping into her squad, Wiegman said: “Absolutely not.
“What we have seen in this tournament is that nothing is easy. The growth of the game has shown in this tournament.
“We’ve not had an easy game at all and that’s what we expect tomorrow – that it will be very competitive and we need to be at our best.
“Everyone who plays us wants to beat us. That’s nothing new. What we have seen in this tournament is game is developing really quickly.
“The games have been very competitive. Nobody can be complacent because that’s inappropriate. It’s very tight.
“I think Nigeria has done really well this tournament and were in a very hard group. We all saw they did very well.
“They are very athletic team, quick in the transition and also want to play. We are aware of their strengths. What we will also try to do is exploit their weaknesses.”