Update: Wednesday’s “Chicago PD” dipped by 25% from the series premiere to score a 1.5 adults 18-49 rating with 5.54 million viewers. It placed second in its 10PM timeslot, landing behind “CSI” (2.0, 10.26 million) and ahead of “Nashville” (1.3, 5.05 million).

Airing in the 10PM timeslot, NBC’s “Chicago PD” did not endure the burden of a head-to-head race with the “American Idol” season premiere.

Unfortunately, it did not avoid a big ratings drop.

“PD,” which bowed to a solid 5.2 overnight metered market rating last week, slipped to a 3.8 in week two. Lead-in “Law & Order: SVU” might have taken a slight adults 18-49 hit against the “Idol” premiere, but insofar as it nearly matched last week’s 4.3 with a 4.2 in the overnight household numbers, it cannot take the blame for the 27% “PD” decline.

“PD” competed with CBS’ “CSI” (6.9 overnight metered market rating) and ABC’s “Nashville” (3.8) in the 10PM timeslot Wednesday.

NBC offered “Revolution” (3.2) at 8PM and “SVU” (4.2) at 9PM.