The sluggish start to the season for Fox’s “The X Factor” continued Thursday as it dropped slightly from its modest premiere of last week to series lows. NBC, meanwhile, got an expected boost for the two-hour finale of its “Million Second Quiz.”

According to preliminary national estimates from Nielsen, “The X Factor” averaged a 1.9 rating/6 share in adults 18-49 and 6.1 million viewers overall — down a tick from its Thursday prelim score of last week (2.0 for its first of two hours). Fox followed up the singing competition with repeats of Tuesday’s series premieres of “Dads” (1.2/3 in 18-49, 3.0 million viewers overall) and “Brooklyn Nine-Nine” (1.1/3 in 18-49, 2.7 million viewers overall).

Ratings for NBC are expected to be revised downward in the nationals as its preliminary estimates include Chiefs football in the Kansas City market. The net’s two-hour finale of “Million Second Quiz” averaged a 1.4/4 in 18-49 and 5.4 million viewers overall from 8 to 10 p.m., the show’s best demo delivery in its last eight nights. At 10, the Peacock aired the Valerie Harper-centered special “Valerie’s Story” with Meredith Viera (1.0/3 in 18-49, 4.4 million viewers overall).

ABC had a football preemption in Philadelphia for the Eagles game, so its numbers are also expected to come down a bit in the nationals. In the early scores, “Wipeout” earned a 1.2/4 in 18-49 and 4.4 million viewers overall, followed by repeats of May’s season finales of “Grey’s Anatomy” (1.4/4 in 18-49, 5.1 million viewers overall) and “Scandal” (1.2/4 in 18-49, 4.1 million viewers overall).

In advance of the debut of its four-comedy Thursday block next week, CBS last night aired repeats of “The Big Bang Theory” at 8 (2.1/7 in 18-49, 8.8 million viewers overall) and 9 (2.2/6 in 18-49, 7.9 million viewers overall) and encores of “Two and a Half Men” at both 8:30 (1.6/5 in 18-49, 7.0 million viewers overall) and 9:30 (1.7/5

Next Thursday should feature plenty of fireworks, as the night features the season premieres of “The Big Bang Theory,” “Glee” and “Grey’s Anatomy,” among others, as well as the much-anticipated new comedies “The Crazy Ones” on CBS and “The Michael J. Fox Show” on NBC.

Preliminary 18-49 averages for the night: CBS, 1.6/5; Fox, 1.5/5; ABC and NBC, 1.3/4; Univision, 1.2/4; Telemundo, 0.4/1; CW, 0.2/1.

In total viewers: CBS, 6.7 million; NBC, 5.1 million; ABC and Fox, 4.5 million; Univision, 3.1 million; Telemundo, 1.1 million; CW, 0.7 million.