LAST JANUARY, the NFL announced it was going to put replay monitors on every sideline so that trainers and team physicians could review possible injuries, including concussions.

They started using them during the 2011 playoffs and have had them on sidelines for every game this season.

"Concussions have been the motivating force behind this," Eagles trainer Rick Burkholder told the Daily News in early August. "There's a lot of times where if you didn't see the injury, you don't really know [the severity]."

So, on Sunday, after tight end Brent Celek suffered a concussion after getting hit in the head by Bucs linebacker Lavonte David on the first play of the game, one of the first things Burkholder did was go to the replay monitor so that he could see exactly what happened.

Unfortunately, the monitor was out of order.

"It wasn't working," Burkholder said. "Because Brent was complaining of neck pain and said he had lost consciousness, I wanted to see it on the monitor. I went over and they said it wasn't up and running."

That's the bad news. The worse news is Burkholder said it isn't the first time this season that the sideline replay monitor has been inoperable.

"I wish I could say it was, but it's not," the Eagles trainer said.

NFL spokesman Greg Aiello said there was an issue with the power supply for one of the components that processes the video that is sent down to the field. He said the issue

was addressed during the game, but field viewing wasn't available when Celek's injury occurred.

"Similar to instant replay, it's a computer-based system that has periodic issues that are generally addressed immediately with minimal disruption," Aiello said.

Last December, the league also began putting a certified athletic trainer in the booth at all games to look for potential concussions. He also has access to a monitor, which was presumably working Sunday.