By Pat Gallen

PHILADELPHIA (CBS) — On Sunday night, in prime time, against the third-ranked defense in the NFL, Eagles quarterback Carson Wentz may have to lean on guys like John Hightower, Deontay Burnett and Richard Rogers. That’s because the Birds will be without DeSean Jackson, who was ruled a no-go with a hamstring injury, so points might be at a premium against the 49ers in San Francisco.

There’s not a lot of time to get ready for one of the best defenses in football. The 49ers are allowing under 190 yards passing and just a shade over 15 points per game.

The Eagles are struggling to just find people to catch the ball.

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On Thursday, it was a mess of missing players for Wentz. In fact, the only wideout on the active 53-man roster that took part Thursday was Greg Ward.

Head coach Doug Pederson said Friday Jackson is day-to-day but has been ruled out for Sunday.

Jackson joins rookie wide receivers Jalen Reagor and Alshon Jeffery and tight end Dallas Goedert on the sidelines. Second-year wideout JJ Arcega-Whiteside is doubtful for Sunday with a calf injury.

Pederson says Wentz has to be ready for anything.

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“You know, we’ve just talked to him a lot this week about that and not specifically this week but really any week. It doesn’t matter if we have all our weapons available or not, it’s a matter of letting those guys work,” Pederson said. “It’s our job as coaches to make sure they’re prepared and ready to go with their jobs and Carson just handling and running the offense like he knows how. This is no different. If anything, there’s more communication probably like it was at the end of the season last year when some of those new guys and young guys were playing, the communication picks up just a little bit more.”

Running back Miles Sanders was limited Thursday but said he’s ready to go for the 49ers game. Expect to see a lot of Sanders if some of the Birds’ receivers can’t play.

Speaking of banged up, the 49ers were missing their starting quarterback, running back and tight end, but they still went off on the New York Giants in a 36-9 rout last week.

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The Niners will again start Nick Mullens under center against the Eagles.

Pederson says no matter who they start, the Birds’ D will be prepared.

“They keep it very basic and vanilla and let their players play. And they both run the offense extremely well as we saw last week with Nick. You just have to go in and prepare,” Pederson said. “It’s different than say you got Jimmy Garoppolo and Michael Vick, you got two different types of quarterbacks, two different styles. Then you might have to plan differently. I think you go with your gameplan what it is, you execute it, you focus on your job no matter who’s playing quarterback.”

In other Eagles injury news, cornerbacks Avonte Maddox and Trevor Williams are out Sunday.

Fletcher Cox was absent from practice Friday for personal reasons, but he is expected to suit up Sunday.