Preview: 49ers Pass Game vs. Eagles Pass Defense

The Eagles pass defense has more holes than Swiss cheese, but it still can threaten the 49ers offense if it's not careful.

The Eagles currently rank 29th in passing yards allowed and 31st in passing touchdowns allowed -- not good rankings. Their linebackers and safeties are slow and struggle in coverage, and their cornerbacks are old. Darius Slay is still good even though he's 32, but the rest are vulnerable.

But these teams faced each other in January, and the Eagles pass defense won the game on the 49ers' first offense series because no one could block Haason Reddick, who injured Brock Purdy's throwing elbow almost immediately.

The 49ers called a play-action pass -- the foundation of their aerial attack -- and tried to block Reddick, a premier edge rusher, with backup tight end Tyler Kroft, who simply whiffed. Bad matchup. Bad play call.

Brock Purdy and the 49ers pass game should perform well as long as Shanahan doesn't call too much play action. Because Reddick and the Eagles pass rushers won't react to the run fake -- they will hunt Purdy, who will have his back to them. That's how he got injured in Philadelphia last season.

Purdy will have to line up in the shotgun, drop back and throw the ball quickly before Reddick pounces on him. Because 49ers right tackle Colton McKivitz can't block Reddick one on one. That's the matchup to watch. The 49ers will have to give McKivitz as much help as possible, which means George Kittle might have to block.

Advantage: Eagles.