The second-year cornerback was having a decent game before leaving in he second half with what was called a groin injury. The team then announced he was not expected to return, a grim sign the injury may have been serious. Not calling a player 'questionable' or even 'doubtful' to return is often a signal that the injury could be significant.
In this case, however, it may have been the Bengals being cautious with an injury they already knew Dennard was dealing with. ESPN's Coley Harvey reports Dennard tweaked his groin in one of the joint practices with the Giants before injuring it during Friday night's game. Dennard decided to play through the pain on Friday, but after 18 snaps, called it a night.
As for when Dennard could return, that decision is being left up to the coaches, as Harvey notes:
It doesn't sound as if Dennard is in jeopardy of missing the regular-season opener, but he isn't necessarily going to be rushed onto the field, either. Asked Saturday how quickly he believed he could return, Dennard reiterated the fact that he played Friday after even originally suffering the injury was likely a promising sign. Like others who are banged up, he deferred his injury timetable to coaches and trainers. When they felt he was ready, he would be back, he said.
Prior to this week, Dennard was having a good showing in training camp, just as was the case last year when he was a rookie. Unfortunately, in 2013 Dennard suffered a hip injury during a special teams play against the Jets (second preseason game) that knocked him out he rest of the preseason and the regular-season opener.
That ultimately helped lead to Dennard falling behind the eight ball and only getting 77 snaps as a rookie. Hopefully, his latest injury isn't another that could cost him significant time.