Jackson, ruled out for the game on Friday, injured his right thigh in the Rams' 34-14 win over Dallas on Oct. 19. He missed the next game at New England and had just 17 yards on seven carries in a 34-13 loss to Arizona last weekend.

Darby has two carries for 9 yards in his NFL career. Signed off Atlanta's practice squad Oct. 15, he was a seventh-round draft choice last year by Tampa Bay and played in one game for the Buccaneers.

Samkon Gado, signed by the Rams on Tuesday, will be Darby's backup. Travis Minor is still dealing with a concussion and will not play.

Also inactive for the Rams were cornerback Tye Hill, linebacker Chris Draft, guard Roy Schuening, offensive tackle John Greco and defensive end Eric Moore. Brock Berlin was the No. 3 quarterback.

For the Jets, leading tackler David Harris was inactive, as expected, after reportedly having surgery earlier this week on his injured groin. The linebacker will miss at least two to three weeks after being hurt in the second quarter of New York's 28-24 victory over Kansas City on Oct. 26.

Safety Eric Smith (head) and tight end Bubba Franks (hip) were also previously ruled out for the game.

Also inactive for the Jets were kicker Mike Nugent, cornerback Justin Miller, wide receiver David Clowney and running back Marcus Mason. Brett Ratliff was listed as the No. 3 quarterback.