NFL owners have agreed to several rule changes to the kickoff play to promote better safety practices. (0:45)

ATLANTA -- NFL owners gave temporary approval Tuesday for a proposal designed to make the kickoff safer. The new rule will be in place for the 2018 season but will be evaluated next spring based on injury numbers and other factors.

The NFL fast-tracked the rule after medical data revealed that concussions were five times more likely to happen on kickoffs in 2017 than on other plays. A group of nine special-teams coaches authored the bulk of the plan earlier this month. While it won't look much different to many fans, the new format is intended to reduce the number of high-speed collisions involved in the play.

The primary changes include:

The elimination of running starts for kickoff coverage teams

A requirement that eight of the 11 men on the return team must be aligned in the "setup zone" within 15 yards of the ball

No blocking within the "setup zone" until after the ball touches the ground if it is not first caught

The elimination of two-man wedge blocks

Kickoff team must have five men lined up on either side of the ball, a move that will limit schemes designed to get free runners in coverage down the field.

The NFL also tweeted out more details on the new kickoff rules.

Concussions on kickoffs actually dropped by about 20 percent from 2016 to 2017, but the league still scrambled to address the issue after the season. For that reason, it's unclear how much further the concussion numbers must drop to ensure a second season under this rule.

If the numbers don't improve to the league's liking, more dramatic changes -- including the elimination of kickoffs -- would be on the table for 2019.

Assembled here for their spring meetings, owners also formally approved an expansion of replay review to include all ejections. That was the final piece of a rule, approved in March, that will penalize and possibly eject players for lowering their helmets to initiate contact against an opponent.

Moving forward, all ejections will be reviewed to confirm they were the result of flagrant acts.

The expansion represents a philosophical shift in the league's approach to replay review. Historically, the league has limited reviewable plays to objective calls: whether a player was in bounds, for example, or if he was down before he fumbled. Reviewing ejections requires a judgment on whether an act was indeed flagrant, by definition a subjective decision. But the league's competition committee, as well as owners, didn't think ejections for the new helmet rule would be fair without a chance to ensure they were merited.