The NFL has acknowledged that the playoff-bound San Diego Chargers should have been penalized on the final play of regulation in Sunday's game against the Kansas City Chiefs.

Chiefs kicker Ryan Succop missed a 41-yard field goal attempt with four seconds left in regulation, a kick that could have eliminated the Chargers while vaulting the Pittsburgh Steelers into the playoffs.

San Diego beat Kansas City 27-24 in overtime to clinch the AFC's second wild card.

But based on a new rule this season, the Chargers should have been flagged for illegal formation prior to Succop's missed field goal, a 5-yard penalty that would have given Kansas City a 36-yard game-winning attempt.

"On the play, San Diego lined up with seven men on one side of the snapper," the league said in a statement released Monday morning. "This should have been penalized as an illegal formation by the defense."

Ryan Succop's missed 41-yard field goal try against the Chargers should have been retaken, and from 5 yards closer, but the refs missed a call, the NFL acknowledged Monday. AP Photo/Denis Poroy

The rule (Rule 9, Section 1, Article 3) is in relation to the overloading of one side of the formation when defending a field goal. Replays clearly showed the Chargers had seven players lined up on the right side of the defensive formation.

"The rule was adopted this year as a player safety measure," the league's statement said. "The penalty for illegal formation by the defense is a loss of five yards.

"This rule is not subject to instant replay review. Had the penalty been assessed, it would have resulted in a fourth-and-7 from the San Diego 18 with 0:04 remaining, enabling the Chiefs to attempt a 36-yard field goal."

Had the Chargers lost Sunday, the Steelers (8-8) would have claimed the No. 6 seed in the AFC playoffs based on conference tiebreakers.

Instead, San Diego (9-7) will visit the Cincinnati Bengals on Sunday in the wild-card round.

ESPN.com Chargers reporter Eric D. Williams contributed to this report.