Wolves defender Richard Stearman has been drafted into the England Under 21 squad after three players were forced to withdraw.
Manchester City duo Micah Richards and Michael Johnson along with Aston Villa's Craig Gardner have all withdrawn from the squad because of injury.
Under 21 boss Pearce has moved to bring in Stearman to provide cover for Friday's clash with Portugal.
A draw would be good enough to ensure qualification for the play-offs for next summer's European Championship finals, but Pearce is aiming to get a win against Portugal.
"We know that if we beat Portugal, it could be enough to knock them out of the tournament in the qualifiers," Pearce told TheFA.com.
"They are one of the top six sides in Europe, so we could do ourselves a very big favour.
"This is the most important game we've had for a year and a half and it's where all our hard work in the play-offs comes to fruition.
"It could make or break our season and we're all aware of it but we are all ready for the challenge."