HOUSTON — The NFL and the players’ union announced a series of changes Friday to the way potential concussions are handled during games following an ugly incident in which Texans quarterback Tom Savage was allowed to return to the field after a hit left him on the ground, arms shaking.

Among the changes is the addition of an expert watching games from a central location with the authority to alert sideline medical teams to look into an incident. And if a player shows signs of a seizure or similar responses, as Savage did, they will be removed from the game and cannot return.

The NFL has been under increased scrutiny the past several years over player safety when it comes to head injuries..

The jarring injury to Savage prompted a joint review of concussion protocol by the NFL and the NFL Players Association. He was hurt in the second quarter of Houston’s 26-16 loss to San Francisco on Dec. 10 when he was driven to the ground on a hit by Elvis Dumervil. Replays showed Savage looking dazed after his head hit the ground with both of his arms shaking and lifted upward. He was taken to the medical tent where he stayed for less than three minutes before returning to the bench and going back in for the next series.

Savage threw two incompletions on that drive, and Houston’s team doctor approached him after he returned to the sideline at the end of that possession. He was evaluated again and taken to the locker room after it was determined that he did have a concussion.

JETS: New York announced Friday it extended the contracts of General Manager Mike Maccagnan and Coach Todd Bowles, keeping the pair for at least the next three seasons through 2020.

The extensions are for two years each, according to a person with direct knowledge of the contracts.

The announcement came two days before the Jets complete their season at New England. New York is 5-10 and will miss the playoffs for the seventh straight year and the third under Maccagnan and Bowles.

New York Jets right tackle Brandon Shell will not play in the season finale against the New England Patriots because of a concussion.

DOLPHINS: Miami left tackle Laremy Tunsil is doubtful for Sunday’s game against Buffalo because of an ankle injury.

JAGUARS: Jacksonville defensive end Yannick Ngakoue has been fined $30,387 by the NFL for making physical contact with a game official during a loss to San Francisco last Sunday.

Receiver Allen Hurns is expected to play at Tennessee, his first action since Nov. 12, after missing the last six games because of a high-ankle sprain.

TITANS: Tennessee will play without running back DeMarco Murray in its important regular-season finale against Jacksonville. The Titans face a win-and-in situation Sunday as they attempt to reach the postseason for the first time since 2008.

With Murray out, the Titans will start Derrick Henry at running back.

BUCCANEERS: Tampa Bay will keep Coach Dirk Koetter, putting an end to the rumor of Jon Gruden returning, accoring to the Tampa Bay Times.

COWBOYS: Dallas put left tackle Tyron Smith and cornerback Orlando Scandrick on injured reserve before the season finale at Philadelphia.