Lamb exited Sunday's game against the Falcons with a shoulder injury, Calvin Watkins of The Dallas Morning News reports.
Prior to that, Lamb had caught eight of his 12 targets for 47 yards and carried twice for 15 yards. In his absence, QB Cooper Rush -- who is in for Dak Prescott (hamstring) - has WRs Jalen Tolbert, Jalen Brooks, KaVontae Turpin and Ryan Flournoy to throw to.