NFL Experiment solved

Here is a response from Lake Affected on the infamous green dot:

The green dot is the in-helmet communication link between the QB and the offensive coordinator.I heard it was brought about because the Seahawks also used backup QB Seneca Wallace as a wide-out on occasion and when they did, both he and Hasselback had in-helmet communications on the field at the same time.Only one player is allowed to have the earpiece on the field at a time.

Thanks for the tip Jason.