Canavan, 19, twill join Noel King's side ahead of Friday's friendly against Portugal.
After that he will not return to Glanford Park, instead heading to Shropshire to see out the season playing for the League Two Shrews.
Canavan was born in Leeds but has an Irish passport. He has made a total of 20 appearances for the Iron, but has not featured this season since November due to a knee injury.
“Portugal are a talented side and include players such as Manchester United star Bebe, their recent 3-1 victory over Sweden proves that they will be a big test for us," said Noel King, the U21 coach.
"After the Portugal match, we have one remaining friendly against Austria in August, which means that we will have to take every available opportunity to fine-tune our preparation ahead of the European Championship qualifiers."