Motta, Brazilian-born, was given the all-clear to play for Italy by FIFA last week.
"We were following Motta even when Andrea Pirlo was available, he is not a replacement," said Prandelli.
"We want a technical midfield, with plenty of quality and he fits the bill. He can play both as a playmaker and as a central midfielder."
Juventus striker Matri was also included for the first time less than seven days after completing a loan move to the Turin giants.
"We were watching him even before he arrived at Juventus," Prandelli insisted. "He's a finisher, but can play out wide too."