CHICAGO -- Calvin Johnson's no-catch just might become a catch in the future.

The NFL expects to review the rule that cost the Lions' star receiver a potential winning touchdown in a season-opening loss to Chicago. After Johnson went to the turf with possession, he placed the ball on the ground as he ran to celebrate. It's been one of the season's most discussed -- and dissed -- calls.

"The going-to-the-ground rule definitely will be discussed," NFL competition committee co-chairman Rich McKay said Tuesday at the league's fall meetings. "It's been discussed the last couple of years. It's a difficult rule. It was made for on-field officials, not as much for people watching on TV."

"There's a definite conflict," he added. "We have to go back and look if we extended it too far."

Against Chicago, with Detroit trailing 19-14, Johnson leaped to grab a pass from Shaun Hill in the end zone. He got both feet and a knee on the ground before putting the ball on the grass and beginning to celebrate. It was ruled incomplete because Johnson didn't maintain possession of the ball throughout the entire process of the catch.

The competition committee will meet after the Super Bowl and then suggest any rules changes to team owners at the league's spring meetings in March.

McKay also said another move that drew criticism, switching the umpire from behind the defense line to behind the offensive backfield, is working. He hasn't seen any video of an umpire being hit by another player; last season, there were "between 105 and 115 hits on video."

But the move has affected the number of offensive holding penalties, which were up through four weeks. Placing the umpire behind the offense apparently has given him a better view of blocking on the line.

Several quarterbacks, particularly Peyton Manning, complained in the preseason that the new positioning of the umpires delayed spotting of the ball to restart play.

"That has not been an issue like some thought it would be in the preseason," said McKay, the president of the Atlanta Falcons.

One trend the league is concerned with is the number of helmets that have flown off players' heads. McKay informally charts such things, and the league office is keeping count.

"We're going back to each manufacturer and asking why it's happening," he said. "It's definitely something we should be looking at. The union ... and everyone is in on this issue."

McKay said he was encouraged that some of the hits on defenseless receivers have disappeared, which he credited to "players adjusting to the way they play the game."