The Steelers needed depth at RB so they shipped one of their young LBs to Philly. (USATSI)
The Steelers need a running back and the Eagles need to bolster a defense that was among the worst last season -- and didn't look much different through two preseason games. To that end, Pittsburgh has traded outside linebacker Adrian Robinson to Philly in exchange for running back Felix Jones, the Steelers have announced.

Running back Le'Veon Bell, the Steelers' rookie second-round pick, is sidelined indefinitely with a mid-foot sprain. He had impressed coaches during training camp, but lasted just five plays in his preseason debut on Monday and he could be out of action for several weeks. That leaves Jonathan Dwyer, Isaac Redman and third-down back LaRod Stephens-Howling. And now, Jones, the Cowboys' 2008 first-rounder who was selected 22nd overall, one pick before the Steelers drafted Rashard Mendenhall, who is now in Arizona.

There was speculation that Jones might not make the final roster in Philly, and Robinson, the second-year linebacker out of Temple, may have been facing a similar fate in Pittsburgh because of all the young talent at the position.

It's not clear how the Steelers will use Jones, who has been something of an underachiever in his five years in the NFL after a standout career at Arkansas. In Dallas, he was supposed be what the Chiefs have in Jamaal Charles or the Bills have in C.J. Spiller. It never happened, and Jones wasn't re-signed in the offseason. In May, he signed a one-year deal with the Eagles, and now he'll head west on the Pennsylvania Turnpike to Pittsburgh.

In his career, Jones rushed for 2,728 yards (4.8 average) and 11 touchdowns. He also has 127 receptions for 1,062 yards and 3 touchdowns. Robinson, meanwhile, appeared in 12 games last season and didn't register a tackle.