BRISBANE, Australia -- England's star midfielder Keira Walsh is back in full training and could make a stunning comeback against Nigeria on Monday.

The FA confirmed Sunday morning all 23 England players were training at their base at the Central Coast Mariners, including Walsh who picked up a knee injury against Denmark.

It is unclear at present whether Walsh will be in the mix to feature against Nigeria in their Round of 16 knockout match, but Sarina Wiegman is expected to confirm her availability later on Sunday at a press conference 18.45 local.

The news of Walsh's return will come as a huge boost for England. Back when she injured her knee against Denmark, there were fears she had suffered a tournament-ending injury. She was stretchered off in the 35th minute of the match after her right knee buckled underneath her as she stretched for a pass.

The FA confirmed a day after the Denmark match she had avoided ACL damage, but wouldn't put a timeframe on her recovery. But the fact she stayed with the camp rather than being flown home sparked hopes she would play again in the World Cup.

The announcement she'd returned to full training on Sunday came just 48 hours after the FA confirmed she was undergoing an individual training programme, but didn't feature on the grass on Friday.

Without Walsh, England deployed a 3-5-2 formation against China to great effect, winning the match 6-1. After that match, Lucy Bronze was asked whether England would continue with that formation or revert back to their usual 4-2-3-1 if Walsh returned.

"We have shuffled things about a little bit and it keeps other teams on their toes. They don't know what to expect, it makes us unpredictable," Bronze said.

"If Keira does come back and play, who is to say how we will play. We might keep this formation with her in it.

"We need to be unpredictable, we needed to refresh things, you need that in the knockout rounds."