Decker is expected to have an MRI this week to determine the severity of the injury. He didn't practice on Wednesday and wasn't spotted at the field, an indication the injury could be serious.
Coach Todd Bowles said he's "not sure yet" if Decker will play Sunday against the Seattle Seahawks.
"Anybody that doesn't practice I'm concerned about," Bowles said. "He came back last week without practicing, so we just have to wait and see."
Actually, Decker wound up practicing two days and wasn't listed on the injury report. He played every offensive snap in the game, finishing with only one catch in the 24-3 defeat. He didn't mention the shoulder aggravation until Tuesday, Bowles said.
The Jets (1-2) could be thin at wide receiver because rookie Jalin Marshall is out at least two weeks with a torn labrum in his shoulder. He will try to rehab the injury, but he could have season-ending surgery if that fails.
Jalin Marshall is the No. 4 receiver (five catches for 64 yards) and returns punts and kickoffs. Rookie Robby Anderson would move into the No. 4 role and also could replace Marshall in his returning jobs.
If Decker is out, too, the Jets would line up with Brandon Marshall, Quincy Enunwa and Anderson as the top three receivers, with seldom-used rookie Charone Peake as the No. 4. Brandon Marshall still isn't 100 percent, dealing with a minor knee sprain.
Bowles said the Jets may add a receiver to the roster.
Newly acquired tight end Austin Seferian-Jenkins, cut last week by the Tampa Bay Buccaneers following a DUI arrest, has receiving skills, but he probably won't be ready to play by Sunday. In fact, he didn't arrive until Wednesday afternoon and won't make his practice debut until Thursday.
Cornerback Darrelle Revis tweaked an ankle on Wednesday and didn't practice, but it doesn't appear to be serious.
"Not much [concern]," Bowles said.