PHILADELPHIA (973espn.com) — On a day the Eagles were down four key contributors from their secondary, the team added a piece when they were awarded safety Trae Elston off waivers from the Buffalo Bills.

Es expected safety Rodney McLeod and hybrid Jaylen Watkins missed practice while nursing hamstring injuries. In concerning news, however, McLeod's presumptive replacement on Sunday against the New York Giants, Corey Graham, was also on the sideline with a hamstring issue.

That comes on the heels of losing cornerback Ronald Darby to a dislocated ankle in the season opener against Washington.

Without McLeod and Graham, the Eagles were down to two healthy safeties -- Malcolm Jenkins and Chris Maragos -- although linebacker Kamu Grugier-Hill played the position in college at Eastern Illinois.

Philadelphia tried to sign safety DeAndre Houston-Carson off Chicago's practice squad but the Bears responded by elevating him to their own 53-man roster.

Elston was waived earlier this week and has already become a bit of a journeyman since entering the league as an undrafted free agent out of Ole Miss in 2016.

Prior to his stint with the Bills, Elston also had cups of coffee Cleveland, Tampa Bay, and New Orleans.

The Buffalo to Philadelphia pipeline has been pretty significant when it comes to the defensive backfield in recent years as Elston is just the latest in a lineup that has included the now-departed Ron Brooks and Leodis McKelvin as well as Graham and Darby.

-John McMullen covers the Eagles and the NFL for 973espn.com. You can reach him at jmcmullen44@gmail.com or on Twitter @JFMcMullen