Coloccini broke two bones in his back after landing awkwardly as he made an overhead clearance during his side's 4-2 Premier League win against Southampton on February 24.
The 31-year-old has been allowed to return home to Argentina for a week to work with his national team's medical staff and Pardew is expecting him to be sidelined for some time.
"Colo has gone back to Argentina. There's no treatment he can have, he's broken two of the bones in his back," Pardew said. "We think it's going to be anything between three and seven weeks. He's gone back for a week."
