As expected, Jay Leno will get an early jump on the fall season as his primetime yakker bows the week of Sept. 14.

NBC will also give its Thursday-night comedy block a head start on fall, launching its four-laffer lineup on Sept. 17.

That night promises to be competitive, as ABC is bowing highly anticipated drama “Flash Forward” and CBS is returning “Survivor” on that same date.

Thursday nights will continue with “Saturday Night Live Weekend Update Thursday” at 8 p.m., followed by “Parks and Recreation” at 8:30, “The Office” at 9 and newbie “Community” at 9:30 until Oct. 8, when “SNL” completes its Thursday-night run and “Community” slides down to 8 p.m.

Also that night, “The Office” will air as an hourlong special. Emmy winner “30 Rock” then returns on Oct. 15 at 9:30 p.m.

Meanwhile, Tuesday staple “The Biggest Loser” will also return a week before the official start of the fall season, as the two-hour series bows its season premiere on Sept. 15.

“Heroes” is set to return on Monday, Sept. 21, with a two-hour premiere; frosh drama “Trauma” then slides into its 9 p.m. slot on Sept. 28.

The net’s Wednesday lineup — new drama “Parenthood” and the return of “Law & Order: SVU” — clocks in on Sept. 23.

And the Friday sked of “Law and Order” and “Southland” launches its new season on Sept. 25.

“Saturday Night Live” has its season premiere on Sept. 26; that same night, NBC starts airing repeats of “Trauma” and “Law and Order: SVU” alongside “Dateline NBC.”

“Sunday Night Football,” as previously announced, returns Sept. 13 with the Chicago Bears at the Green Bay Packers.