Christopher Meloni confirmed in May that he would not reprise his role as Elliot Stabler for the NBC drama's 13th season.
Discussing the character's exit, Leight told TV Done Wright: "A squad room is a family, and the dynamic will change enormously when a leader departs. I want to track those changes and shifting alliances. I also want the audience to know the loss will be dealt with, not ignored."
He also confirmed that Stabler's exit will occur off-screen, but insisted that the "abrupt" departure will be addressed.
"The reality is Chris left abruptly, and so in the squad room, his character's departure will be handled similarly," he explained. "Closure is something therapists strive for, but real life has lots of jagged endings."
Leight, who replaced Neal Baer as SVU's executive producer, also admitted that Christopher Meloni had been "guarded" on the two occasions they had met.
"I came in as Chris was walking out, and I don't think anyone saw it coming," he recalled. "Usually these negotiations go down to the wire and end with a new contract. This time it broke late, the other way."
He added: "I guess someday he might come back, or make an appearance. But the show has to move on as if he won't. I can't spend a whole season pining."
Meloni previously insisted that he has "no regrets" over his SVU exit and will next be seen in Zack Snyder's Superman film reboot Man of Steel.
Law & Order: SVU returns to NBC on Wednesday, September 21 at 10/9c.
> Andre Braugher 'close to joining Law & Order: SVU
Watch a trailer for the new season of Law & Order: SVU below: