One of the byproducts of the new rule permitting one defensive player to hear his coach’s instructions through a communication device in his helmet is that we’ll see twice as many green dots this year as we saw last year.

The green dots, of course, are the stickers that made their debut last year on quarterbacks’ helmets. They’re used to let the officials know which players have radios in their helmets, and to ensure that teams don’t have more than one player on the field at a time hearing the coaches’ instructions. Now we’ll see defensive players wearing them in addition to quarterbacks.

But the NFL Network’s behind-the-scenes coverage of today’s league meetings demonstrated how those green dots could cause headaches around the league.

The defensive player who wears the green-dotted helmet will be told to report to the umpire before he takes the field. But Vikings coach Brad Childress and Panthers coach John Fox both raised concerns at today’s meeting about whether it was feasible for a substituting defensive player to check in with the umpire before lining up.

For instance, Childress pointed out that he might want to use a setup in which he had a linebacker wearing the helmet radio in the base defense, and a defensive back wearing it in the nickel package. If it’s third-and-10 and the nickel back replaces the linebacker, does it make sense to force him to check in with the umpire and point to the green dot on his helmet between plays?

Falcons executive Rich McKay, who was running the meeting in his role as a co-chair of the Competition Committee, said it would be up to the defensive player to report to the umpire. McKay didn’t seem too concerned about problems arising, and apparently Childress and Fox weren’t either, because both the Vikings and Panthers voted for the proposal.

But it seems likely that there will be at least one play this year when a defensive player is out of position because he was too busy making sure the umpire knew whether he had the green dot on his helmet to get lined up on time. With that concern — and considering how ugly the dots are — the league would be better off finding a way to implement this rule without the green dots.