Amaro was running a route early during the practice Wednesday when he stopped short, went down on a knee and clutched his back while grimacing. He was looked at by trainers on the sideline and then headed to the locker room.
Amaro, the Jets' second-round draft pick last year, didn't return to the organized team activities. Coach Todd Bowles was uncertain of Amaro's status after practice, saying only that he was told the tight end was ''sore.'' Bowles also couldn't confirm that the injury was to Amaro's back.
Amaro had an inconsistent rookie season, but finished tied for second on the team with Jeremy Kerley with 38 receptions.
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