Reuben Foster Injured At Redskins' Practice, Carted Off With Cast On Leg

More bad news for Reuben Foster ... the Washington Redskins LB was carted off the field Monday after suffering a scary injury during his first practice ever with the team.

Reporters on the scene say the ex-Alabama star -- who the 'Skins just picked up a few months ago after the 49ers cut him -- injured his left leg during an on-field play.

Foster reportedly was pushed to the ground ... and was in clear and obvious pain afterward -- punching the grass and screaming out loud.

Trainers put Foster's leg in a cast and carted him off the field ... and it's unclear right now how severe the injury is -- but things don't look good.

It's another piece of bad news for Foster -- who's dealt with multiple issues the past two years including two separate domestic violence incidents as well as a marijuana arrest.

Foster appeared to have all his troubles behind him after signing with the Redskins back in November -- the NFL said he would NOT be suspended after his most recent domestic violence arrest -- and he looked poised to be a starter for Washington this season.