If the Eagles fail to make the playoffs, Sunday’s game will be one that haunts them. Like last week’s seven-point loss to the Patriots, it’s a game they easily could have won but didn’t.

Here are my five reasons they didn’t:

All those turnovers

I’m not breaking any news here by revealing that it’s next to impossible to win a game when you turn the ball over five times. Before Sunday, the Eagles had five or more turnovers in a game nine times since 2000. They lost eight of those nine by an average of 21 points.

Sunday was the fifth time this season that the Eagles have had two or more giveaways in a game. They lost all five of those games.

Three of their five turnovers in Sunday’s loss came in Seattle territory and killed potential opportunities for points.

The first of Carson Wentz’s two interceptions came early in the second quarter after the Eagles had driven from their 1 to the Seattle 33.

The Eagles were in 13-personnel with an extra offensive lineman. But Seattle, rushing six, still managed to get pressure on Wentz and force an underthrown, off-balance pass to tight end Dallas Goedert that was picked off by safety Bradley McDougald.

Wentz didn’t see the pick. He was on his back after getting leveled by 310-pound defensive tackle Poona Ford.

On a third-and-3 at the Seattle 38-yard line in the third quarter, Seahawks linebacker Shaquem Griffin pushed right tackle Halapoulivaati Vaitai into the backfield and blew up a handoff from Wentz to Miles Sanders, forcing a fumble and ruining another scoring opportunity.

A fumble by Goedert early in the fourth quarter after a 14-yard reception that would have given the Eagles a first down at the Seattle 32 pretty much ended any hope of a comeback.

Brooks’ early exit

Already playing without Pro Bowl right tackle Lane Johnson, who missed the game with a concussion, the Eagles suffered another major blow in the first quarter when Pro Bowl right guard Brandon Brooks had to leave the game because of his anxiety disorder.

With Johnson and Brooks in the lineup, the Eagles have what is arguably the best right-side tandem in the league. Most of the Eagles’ run plays are to their side. They both are exceptional pass protectors. It’s not a coincidence that Wentz’s two worst games of the year have been when Johnson has been hurt.

With Johnson out, the Eagles moved rookie Andre Dillard, who had done a pretty good job subbing for Jason Peters at left tackle when he was out with a knee injury, to Johnson’s right-tackle spot. They hoped playing next to Brooks would help make the left-to-right transition easier for the first-rounder.

But Brooks left after just 12 snaps and was replaced by Vaitai. He had enough trouble handling his own blocking responsibilities at a position he has seldom played without serving as a calming influence for Dillard. Dillard played so badly that he was benched in the second half. Vaitai moved to right tackle, and Matt Pryor, who had never played a regular-season offensive snap, went in at right guard.

Vaitai failed to block linebacker Shaquem Griffin on the fumbled handoff between Wentz and Sanders. And Pryor got flagged for a killer holding penalty on a second-and-1 near midfield late in the third quarter when the Eagles were driving.

Carson’s struggles

Playing behind an offensive line that’s missing its two best blockers and throwing to a wide-receiver quartet that came into the game with 14 total receptions is no day at the beach.

But Wentz turned it into a nightmare on Elm Street. Four of the Eagles’ five turnovers had his fingerprints on them. While the final stats show that he completed 33 of 45 passes for 256 yards, that includes a 15-for-18, 156-yard fourth quarter when the Seahawks’ defense was softer than a baby’s blanket.

He missed throws he needed to make all day, starting with his pass behind Ertz on a third-and-7 crossing route on the Eagles’ first possession all the way to a fourth-and-2 misfire to an open J.J. Arcega-Whiteside with eight minutes left in the game.

In between, he overthrew a wide-open Sanders on a third-and-9 play in the red zone, overthrew Sanders on a screen pass, threw the ball behind an open Greg Ward on a third-and-5 and made a bad throw to Ertz on a screen.

Bottom line: Even without Brooks and Johnson, even without Alshon Jeffery and Nelson Agholor, the Eagles might have won this game if Wentz had played up to his capability.

A Penny for your thoughts

The Eagles shut down the Seahawks’ top rusher, Chris Carson, holding him to 26 yards on eight carries. They did a marvelous job of taking Russell Wilson’s legs away from him, holding him to 15 yards on three carries and sacking him six times.

But they weren’t quite as fortunate in neutralizing Rashaad Penny. The second-year running back out of San Diego State, who had just 14 carries in the previous three games, exploded for 129 yards and a touchdown on 14 carries against the Eagles.

He had a 26-yard run in the second quarter to help set up a Jason Myers field goal. Defensive end Derek Barnett let him get outside on a pitch, and linebacker Nigel Bradham couldn’t get off a block by left tackle Duane Brown.

But the big blow was his 58-yard touchdown run right through the middle of the defense early in the fourth quarter, which gave the Seahawks a finally comfy two-touchdown lead.

It was a beautifully blocked play. Just how you would draw it up. Left guard Mike Iupati took out Eagles defensive tackle Anthony Rush. And right tackle Germain Ifedi blocked linebacker Nate Gerry, creating a lane for Penny.

Safety Rodney McLeod, who otherwise played a very good game, was out of position on the play and couldn’t stop Penny. Same with Bradham.

Trickeration II

For the second straight week, Jim Schwartz’s defense had a solid effort soiled by a trick play. Last week, it was Patriots wide receiver Julian Edelman taking a lateral pass from Tom Brady and hitting a wide-open Phillip Dorsett for a 15-yard touchdown in a seven-point loss.

On Sunday, it was the old flea-flicker. On the Seahawks’ second possession, Russell Wilson pitched the ball to Chris Carson, who tossed it back to Wilson, who threw a 33-yard scoring strike to wide receiver Malik Turner, who split McLeod and cornerback Jalen Mills.

McLeod and Mills recovered pretty well, but Wilson, who has the best deep-ball completion percentage in the league this season, was right on target.