Interim manager Robert Page says Wales will appeal against the red card shown to Neco Williams during Wednesday's 3-0 friendly defeat against France.
Williams, 20, was sent off for handball after just 25 minutes in Nice and is now suspended for Saturday's pre-Euro 2020 friendly against Albania.
Wales want the ban rescinded so the Liverpool defender can gain match fitness for their first Euro 2020 game against Switzerland on 12 June.
"It's a bitter one to take," said Page.
"I thought it was harsh to give a penalty in the first place but to send him off was a bitter blow.