Allen left after a helmet-to-helmet collision with Jets linebacker Demario Davis while making a tackle.
Allen's injury puts pressure on an already dinged up secondary. One would expect that Allen will be put through concussion protocols and if so, he might be out into the regular season.
The Jets already have Dee Milliner sidelined with a high ankle sprain and Dimitri Patterson injured much of the preseason. While Calvin Pryor has come back to the field, the Jets can't afford to have three-quarters of their starting secondary unavailable for the first week of the regular season.