The NFL has admitted that the clock operator made an error late in the Rams-Lions game -- a mistake that effectively granted Detroit a fourth timeout.

The Lions ended up winning 27-23 on Matthew Stafford’s 5-yard touchdown pass to Kevin Smith with 10 seconds left.

Following Detroit's second timeout, the Rams had second-and-12 on the Lions 31 with 2:45 left in a 20-20 game. Quarterback Sam Bradford scrambled three yards and slid down inbounds. Line judge Shannon Eastin signaled for the clock to keep winding, but the clock operator stopped the game clock at 2:38.

By the time the game clock was restarted, the 40-second play clock was three seconds ahead. The discrepancy prevented the Rams from running the game clock down to the two-minute warning.

“I was aware of it because I had talked to coach (Brian) Schottenheimer after coach (Jim) Schwartz called timeout and I said ‘We’ll be able to run this down to the two-minute warning,’” Rams coach Jeff Fisher said. “At that time, we had a plan in place so when Sam slid, I told Brian let’s go to two minute and he says we can’t and then I looked up and I realized that there was an error. So in essence, Detroit was granted an extra timeout if you want to look at it from that perspective.”

NFL senior vice president Greg Aiello told the Post-Dispatch via email that "it was a mistake by the clock operator. He stopped the clock incorrectly. The officials did not signal for it to stop."

Due to the error, Fisher changed course, ran the clock down to 2:03 and called time. Had the Rams gotten it down to the two-minute warning, they would have run the ball on third down to force the Lions to use their last timeout.

Instead the Rams went for the first down, Bradford threw incomplete and Greg Zuerlein kicked the go-ahead field goal. The Lions got the ball back at their 20 with 1:55 left.

And they still had a timeout, which they used with 35 seconds left.

The snafu helped Detroit get in position to win the game, rather than kick a tying field goal for overtime.

The NFL hires clock operators. They are not part of the officiating crew.

While the replacement official acted correctly in keeping the clock winding, Fisher noted a clock error is correctable if an official catches it when it occurs. Post-Dispatch beat writer Jim Thomas noted: “That leaves open the question of whether a more experienced officiating crew would have seen the error and corrected it before the next play.”

Fisher stressed that despite the error, the Rams had plenty of chances to make a play to win the game.

O-line hurting: C Scott Wells, the Rams’ second-biggest free agent acquisition, broke his left foot and will be out at least until Week 8. Backup Robert Turner is the only other center on the roster, so the team will add a center this week.

Left tackle Rodger Saffold has a significant neck strain. He was taken off the field Sunday on a backboard in an emergency cart.

“His tests were negative, the CAT scan and X rays were all negative,” Fisher said. “He’s got some further tests to do but at this point, it’s just a significant strain so he was very lucky. That’s good news.”

Wayne Hunter replaced Saffold and appears likely to start Sunday against Washington.

Get more Rams updates and analysis from Larry Hartstein @CBSRams.