Hargitay has already signed on to return, but NBC entertainment president Bob Greenblatt noted that she recently adopted a child and said he was not sure whether she would want to remain with the show beyond the coming season.
Meloni has not signed on yet, but Greenblatt said he didn't expect any obstacles to his return.
Greenblatt said a new detective would join the show "about halfway thorugh the season" and that the character's introduction would lead to a "new relationship" between Hargitay and Meloni's characters. He said NBC was looking at Hewitt as a possible addition.
The show will return in the fall at 10 p.m. on Wednesdays.