Rob Lowe didn’t spend much time on the prime-time TV sidelines.

Less than a full season after his badly handled exit from “The West Wing,” Lowe is back in a new series, “The Lyon’s Den,” which debuts at 10 p.m. Sunday on NBC.

In this drama, he plays Jack Turner, an idealistic lawyer in Washington, D.C. Quite a stretch, no?

Turner is a senator’s son who reviles all that his father stands for. He’s content running a legal-aid clinic that’s funded by the huge law firm where his father is partner emeritus. But he gets sucked back into that world after his mentor supposedly commits suicide, and he’s asked to become a partner at the firm.

The drama, created by Remi Aubuchon (“24”), will be centered on Turner’s search for the truth in a duplicitous world.

While Lowe isn’t playing a particularly novel character, he’s surrounded by a strong ensemble cast, including Matt Craven, Kyle Chandler, James Pickens Jr. and Frances Fisher.

As designed by Aubuchon and a host of executive producers, including Brad Grey (“The Sopranos”) and Lowe himself, “The Lyon’s Den” is a place of intrigue, right from the start. It makes viewers ask what’s really going on behind the glass doors of Lyon, LaCrosse and Levine. This should be one of the season’s best new dramas.

Also premiering Sunday, at 8 on CBS, is “Cold Case,” the latest police drama from Jerry Bruckheimer (“CSI,” “Without a Trace”).

The series centers on Lilly Rush (Kathryn Morris, “Minority Report”), the lone female detective in the Philadelphia homicide squad, who finds her niche when she’s assigned to crimes that have never been solved. She has a knack for finding fresh clues and using new science, and she works to see that no victim gets forgotten.

Rush is that rare character in a Bruckheimer show, being a lead with supporting characters instead part of an ensemble cast. Morris is up to this challenge.

“Cold Case” is a not-so-fresh take on what’s becoming a familiar formula. Still, with such reliable producers as Jonathan Littman (“CSI,” “Without a Trace”) and Shaun Cassidy (“The Agency”, it should flourish as Bruckheimer’s other series have.

Sunday’s last debut, which isn’t reviewed, is “10-8,” which follows Los Angeles Sheriff Department’s rookies in training. It airs at 8 on ABC.