The Nations League game between England and Belgium was temporarily halted for 13 minutes after a clash of heads between Greenwood and Belgium's Jassina Blom.
The English medical staff provided extended treatment to Greenwood on the field before she was stretchered off and given oxygen to stabilise her condition.
Wiegman, while talking to reporters after her team's 3-2 defeat, confirmed that the Manchester City player is "fine" but has symptoms of concussion.
“She’s fine,” said Wiegman about Greenwood. While further elaborating on the player's condition she added: "I haven’t spoken to her yet. I also haven’t spoken to the doctor about it yet, but I heard she’s walking around. Obviously, she has a concussion, but it’s good news that she’s walking around and doing fine.”
The Lionesses added in an official statement on Wednesday afternoon: "Alex Greenwood travelled home as planned and will now return to Manchester City where she’ll continue to be assessed."
The loss to Belgium might prove costly as the Lionesses have to depend on other results going their way to secure Olympic qualification. Wiegman did not hide her frustration after the match but insisted that the team "are not panicking".
“That’s life, and so that’s football too,” said the England manager. “So, we’re not panicking or anything. You could see that we were trying hard, we were trying to find the space and we were trying to have different crosses and play a possession game into the final third, but we just missed in the final perfect touch … although we did create chances to really score goals.”
The Dutch manager went on to admit that Belgium were the better side and also acknowledged that securing a berth for Paris 2024 will be a tall order.
“Very disappointed, we are frustrated too, I think this was unnecessary," said Wiegman. "There were a couple of things we wanted to do better today, but in the end we were too sloppy. They had more counterattacks than they did on Friday, so they did that well and I think we could have done better.
"It’s very tight (Olympic qualification)… we can only do what we can do, so we know what we have to do. We play at Wembley [against the Netherlands], that’s always very exciting, so we’re looking forward to that. But we also want to show again what we are, and that we can do better, against a top opponent of course, too. We have to win and we have to win by more than one, and then we have to win [against] Scotland, so [the task] is very clear.”
England will host the Netherlands on December 1 and then make a trip to Scotland four days later in the final two matchdays of the Nations League.