Redskins safety Brandon Meriweather talks with team physician James Andrews before Monday’s game. (Ray Saunders/The Washington Post)

The need for the Washington Redskins to have safety Brandon Meriweather in their lineup was underscored again in Monday night’s season-opening loss to the Philadelphia Eagles. The Redskins, minus Meriweather, left Eagles receivers open all night and failed to slow down the fast-break offense of Philadelphia’s first-year coach, Chip Kelly.

The Redskins have played 17 regular season games since they signed Meriweather as a free agent prior to last season. Meriweather has played in one of them.

He was on the inactive list Monday night due to a groin injury he’d suffered a week earlier in practice, according to Coach Mike Shanahan. A series of knee injuries limited Meriweather to one game last season. He was limited in training camp this summer and during the preseason. He played the preseason finale. But Shanahan said last week that while Meriweather’s knee was fine, his groin injury had become the issue.

The Redskins regard Meriweather as a versatile player who could be a potential difference-maker for their secondary and their defense as a whole. But they can’t seem to keep him healthy and on the field for games.

Meriweather was on the field during pregame warmups Monday. But when the game began, he was inactive and the Redskins were starting four cornerbacks in their secondary — DeAngelo Hall, Josh Wilson, rookie David Amerson and E.J. Biggers —alongside rookie safety Bacarri Rambo.

“The decision not to play Meriweather is [because] he could not play,” Shanahan said late Monday night. “His groin was too sore.”

Eagles quarterback Michael Vick had a relatively modest 203 passing yards. But Vick threw two touchdown passes and was efficient, connecting on 15 of 25 throws and amassing a passer rating of 112.6. He also missed some open receivers. If he hadn’t, the Eagles’ halftime lead of 26-7 might have been even larger.

“They had a lot of opportunities to be on the field,” Shanahan said. “I’m not sure how many plays they had in the first half but it had to be a lot because we weren’t out there very much. And they did a good job executing. We didn’t do a great job tackling. We gave up a couple big plays. We’ll go back to the drawing board and get better.”

The Redskins’ bid to upgrade a pass defense that struggled mightily for much of last season is off to a shaky beginning.

“We’ve got to get better at tackling,” Shanahan said. “Like I said, we had a couple missed assignments from some young guys that cost us. … We did have too many missed tackles. We had too many mistakes in the first half. You can’t go against a team with a high-tempo offense and you have three first downs and expect your defense to play well in the first half.”

The Redskins had prepared exhaustively to face Kelly’s offense. Yet they still appeared uncertain about how to go about combating what the Eagles were doing. The Eagles also ran for 263 yards, 184 of them by tailback LeSean McCoy.

“That’s the tough thing about it,” Redskins linebacker Brian Orakpo said. “They spread you out across the field and then, [with] most conventional offenses, you would think they’re gonna pass. But they’re running the ball with five [defensive] guys in the box.”

Have a Redskins question? E-mail Mike Jones at with the subject line “Mailbag question” for him to answer it in The Mailbag on Tuesday.

● The Redskins do not practice on Tuesday, but with the quick turnaround for Sunday at Green Bay and a battle of 0-1 teams with high expectations hoping to avoid 0-2, Alfred Morris and Mike Shanahan will speak with reporters in the afternoon.

● Mike Jones’s mailbag.

More on the Redskins:

Five observations from Redskins vs. Eagles

D.C. Sports Bog: Cofield’s club hand | ESPN’s RGIII camerman | More Bog

Opening Kick: What went wrong on Monday night?

For Griffin, a frustrating return to action

Kerrigan might have concussion | Lingering soreness stopped Meriweather

NFL made Griffin hide knee brace | Shanahan defends preseason caution 

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