Fast National ratings for Thursday, August 21, 2014.

ABC got a bit of a bump for the two-hour finale of "Rookie Blood," but that wasn't close to enough to push the network past a "Big Bang Theory" repeat and the rising "Big Brother" on Thursday.

We will, of course, have to see how Thursday Night Football impacts the primetime numbers but, as usual, the answer is likely to be "some." ABC had the Philadelphia preemption, while CBS aired football in Pittsburgh. NBC had preemptions in Jacksonville and Indianapolis, but those probably won't matter very much.

On to the numbers...

Among adults 18-49, CBS averaged a 1.5 rating for Thursday night, tops in the key demographic. ABC was second with a 1.0 key demo rating, followed by the 0.7 key demo rating for NBC and FOX. The CW averaged a 0.2 key demo rating for Thursday.

Overall, CBS averaged an estimated 5.93 million viewers and a 3.7 rating/7 share for Thursday primetime. ABC was second with a 3.1/6 and 4.68 million viewers. FOX's 1.8/3 and a 2.82 million viewers followed, with NBC's 2.77 million viewers and 1.9/3 close behind. The CW averaged 585,000 viewers and a 0.4/1 for the night.

8 p.m. - CBS led the 8 p.m. hour with repeats of "The Big Bang Theory" (8 million and a 1.7 key demo rating) and "Mom" (6.38 million viewers and a 1.5 key demo). NBC's "Hollywood Game Night" repeat was a distant second with 3.69 million viewers and a 0.9 key demo rating, ahead of the 2.7 million viewers and 0.7 key demo rating for ABC's "The Quest." A "Bones" repeat on FOX averaged 2.45 million viewers and a 0.6 key demo rating. The CW's "Vampire Diaries" repeat averaged 630,000 viewers and a 0.2 key demo rating.

9 p.m. - "Big Brother" kept CBS in first for the 9 p.m. hour with 6.97 million viewers and a 2.3 rating among adults 18-49. ABC's "Rookie Blue" averaged 5.2 million viewers and a 1.0 key demo rating. Another "Bones" repeat on FOX averaged 3.2 million viewers and a 0.9 key demo rating, better than the 2.26 million viewers and 0.7 key demo rating for a new "Welcome to Sweden" and a "Sweden" repeat on NBC. The CW's "The Originals" repeat averaged 539,000 viewers and a 0.2 key demo rating.

10 p.m. - "Rookie Blue" rose to 6.14 million viewers and a 1.2 rating among adults 18-49 to lead the 10 p.m. hour for ABC. CBS' "Elementary" repeat averaged 3.62 million viewers and a 0.7 key demo rating, leading the 2.36 million viewers and 0.6 key demo rating for NBC's "America's Got Talent" encore.

All ratings information comes from preliminary Fast National Nielsen data, which includes live and same-day DVR viewing. All numbers are subject to change, particularly in the case of live events.