Cobb exited early in Thursday's practice with a back injury and was listed as a non-participant in the session on the Cowboys' official report, David Helman of the Cowboys' official site reports.
Cobb appeared on the Cowboys' initial injury report Wednesday with a hip issue, but his full participation in practice that day suggested his availability for Sunday's game against the Jets wasn't in any peril. With a new injury now affecting him, Cobb's situation suddenly warrants a closer look heading into the team's final practice of the week Friday. If Cobb is unable to get back on the field Friday, he'll likely carry a designation into the weekend if he isn't ruled out ahead of Sunday.