The team said that Teixeira had been sidelined by illness. Rapax regular Tom Dillmann will represent Teixeira's sponsors, while de Jong will fill in for him in the team's second car.
"It's going to be a really big challenge to step into the GP2 Series in the middle of the season but I can't wait to get out there in Valencia, it's a great opportunity for me," said 19-year-old Dutchman de Jong.
"I know it's going to be the biggest challenge of my career so far but I'm hoping we can do a good job and move forward from Valencia on."
Team owner Gianfranco Sovernigo said Rapax had already been negotiating with de Jong for 2013 after he had tested with the squad during the winter.
"We met with Daniel in the 2012 pre-season tests and we've always been in-touch with the goal of working together for 2013," said Sovernigo. "At the eve of the round at Valencia, the chance came earlier than planned, and for us it's been a logical decision."