Eagles right tackle Lane Johnson, who had played every offensive snap through nine games this season, left the Eagles-Patriots game in the first half with a concussion.

Johnson, one of the game’s best at his position, was replaced by Halapoulivaati Vaitai, who has filled in at both offensive tackle positions, in his four-year NFL career.

A prolonged absence for Johnson could darken the playoff prospects for a team already struggling to overcome a number of injuries to vital cogs. The offense bogged down noticeably after Johnson went down.

Eagles coach Doug Pederson said he hoped to be able to report Monday on Johnson’s situation.

Jason Peters, the 37-year-old left tackle who missed three games with a knee injury, returned to the starting lineup. He took penalties on the Eagles’ first two drives.

Patriots say they were fueled by loss, then bye week

Like the Eagles, the Patriots walked into the Linc on Sunday having last played on Nov. 3. Unlike the Eagles, the Patriots’ pre-bye-week game was a 37-20 loss to the Baltimore Ravens, whose dynamic Lamar Jackson-led rushing attack proved too much for even New England’s defense. In Philadelphia, the Patriots’ defense stepped up, albeit against an offense without much firepower.

After the game, New England players said the tough loss, their first of the season, had motivated them during the bye week.

“It felt great because we had this bye week to do our review and correct mistakes that we had early in the season,” defensive tackle Danny Shelton said. “We had to step it up and use better technique, get after the ball, and make more plays.”

“You never want to lose a game, but you learn from it,” cornerback Stephon Gilmore said. “We got better this week. We had a good week of practice, and played together as a team.”

Jay Train on tracks, but it does not leave station

Jay Ajayi was active for the Eagles’ 17-10 loss but did not play. His absence was not incredibly surprising given he hadn’t played or practiced football since suffering an ACL tear in an Eagles game against Minnesota on Oct. 7, 2018.

He was signed Friday, after Darren Sproles went on IR and Jordan Howard was not cleared for contact in the wake of suffering a stinger against the Bears on Nov. 3. The Eagles’ other healthy, active running backs, Miles Sanders and Boston Scott, struggled, logging a combined total of 64 rushing yards.

Also active Sunday were corner Sidney Jones, who was inactive against the Bears, and wide receiver Jordan Matthews, who rejoined the team during the bye week. Matthews got on the field right away, with DeSean Jackson on IR and Alshon Jeffery missing the game with an ankle injury suffered against the Bears, but Matthews managed only one catch, for 6 yards, on six targets.

Inactive players, other than Howard and Jeffery, were quarterback Nate Sudfeld, defensive end Daeshon Hall, center Nate Herbig, defensive end Shareef Miller, and starting linebacker Nigel Bradham.

The Patriots were missing former Eagles safety Patrick Chung, and they lost wide receiver Phillip Dorsett to an apparent concussion when he was tackled by Rasul Douglas, while scoring New England’s only touchdown.