FLORHAM PARK, N.J. -- New York Jets coach Robert Saleh expressed concern over the new Guardian Cap, saying the protective shells are causing players to use their helmets more than usual -- and he is worried about the potential effects when they are removed later in the preseason.

"I think the spirit of it all is really good. It's got great benefits ... but I do think there's a balance in everything, right?" Saleh said Saturday after practice. "Too much of anything is a bad thing.

"I do think because of the soft blow, it's kind of lending the players to use their heads a little bit more. I do think the first time when they take it off -- anybody who has played football knows the first time you take your helmet off or you hit with the helmet or you have a collision, there's a shock. I do think that if you're waiting until the first game for that shock to happen ... I don't know, time will tell. It's just interesting with those Guardian Caps and what exactly are we trying to accomplish."

Offensive and defensive linemen, tight ends and linebackers are required to wear the cap through the week of the second preseason game. The cap provides a soft, padded outer shell for the helmet. The NFL's goal is to curb the concussion rate. Saleh said he's concerned.

"I am because I think there's an acclimation period that is needed for actual pads for what they are actually going to use in the game," he said. "So if you're waiting until the game to actually feel that, I think it's just going to be interesting to see what type of feedback we get from players."

Dr. Allen Sills, the NFL's chief medical officer, said in a statement: "The brain does not acclimate to head impacts. The Guardian Cap helps mitigate those forces at a time of the season when we see the greatest concentration of them."

No Jets player has complained publicly about the cap. The general feeling is that it just takes some time to get accustomed to them.

"It feels just a little bit heavier," defensive end Jermaine Johnson said. "You feel kind of bobbleheady. It's not too bad. As a defensive lineman, we come out and we strike with our hands anyway."