A surprise onside kick to start overtime in Seattle’s opener at St. Louis left people wondering if Pete Carroll had lost his mind.

Risky? Yes. But not crazy.

Under the rules adopted in 2012, an onside kick to begin overtime can make sense.

If the Seahawks had recovered the kick and scored just a field goal, the game would have ended, because receiving a kickoff is an opportunity to possess the ball.

The Rams recovered at Seattle’s 49 and ended up kicking a field goal. So the Seahawks still had a chance to tie with a field goal or win it with a touchdown. They lost when Marshawn Lynch was stuffed on fourth-and-1 from the Rams 42.

“That is not what was supposed to happen,” Carroll said, explaining he didn’t call for an onside kick. “We were kicking the ball to a certain area of the field and we didn’t hit it right.”

Steven Hauschka said he wanted to kick the ball further down the field but short of the end zone. Carroll wanted the ball to land around the 15 or 20 away from returner Isaiah Pead to possibly force a scramble for it.

Despite Carroll’s intention and the result, other coaches might want to consider an onside kick to start overtime because they would win the game with any score and still have a chance to score if the other team recovers and gets a field goal.

The trade-off for failing to recover the kick is about 30 yards. The receiving team would start near midfield and need at least one first down to get in field-goal range. But if you have a strong defense — like Seattle — it might be worth the risk.

Other questionable calls from Week 1:

uGIANT MISTAKE: Eli Manning and the New York Giants had a chance to put the game away at Dallas on Sunday night with a 23-20 lead late in the fourth quarter, but awful clock management cost them a win.

The decision to pass on third-and-goal from the 1 with 1:34 left and no timeouts remaining for Dallas is a call that will haunt coach Tom Coughlin and the Giants for the rest of the season. Manning threw the ball away with all his receivers covered instead of falling down and letting 40 seconds run off the clock.

Simply taking a knee off the snap would have been a better call because running time off the clock is the priority in that situation. But the incomplete pass followed by kicking a field goal on fourth down gave the Cowboys a chance to win and Tony Romo delivered a game-winning 72-yard drive in 1:27.

“It’s my fault at the end of game,” Coughlin said. “The decision to throw the ball on third down was not a good decision. It should have been a run, whether we scored or not.”

Manning also took the blame.

“I’ve got to sit in there and take the sack and then run off the 40 seconds,” he said.

Manning also made a mistake when he told running back Rashad Jennings not to score on consecutive carries before the third-down pass. Coughlin said that order didn’t come from coaches. A touchdown would have given New York a 10-point lead and iced the game.

“I thought that they may let us score to get the ball back, so that’s why I informed Rashad if they let you score, just go down at the one-inch line. Don’t score,” Manning said.

uGIVE IT TO FORSETT: Trailing Denver 19-13, the Ravens had a first down at the Broncos 16 with 46 seconds left and one timeout remaining. Justin Forsett had run for 20 yards and 9 yards on his only two carries during a drive that started at Baltimore’s 20. The Ravens had time to run the ball, but Forsett didn’t get another carry. Instead, Ravens offensive coordinator Marc Trestman called three straight pass plays. Joe Flacco, who was hurried by Denver’s strong rush all game, threw two incompletions before he was intercepted in the end zone. A run on first or second might have surprised the Broncos and Forsett could’ve broken free with the holes he had on that last possession.