I still think he is a key player. It may look like he is on the outside looking in with Clady's injury -as even with more 3 TE sets the Broncos would rely on Dresseen and Green as blockers before Tamme. What Tamme adds - is a wildcard - you wouldn't want the opposition to think the presensce of Dresseen and Green always means run - or max pass protection. You would send both out to catch passes just to prove up the threat. What Tamme does is radicalize the posibilities - he can stay in to block - he can take a defender out of the front seven to cover him - or in the no huddle he can line up alternatingly in the slot or split out or be kept in to block. The Broncos were looking in training camp for a CB/S combination - on offense he provides a TE/WR combination. Couple that with the fact that Tamme and Manning relate intuitively on the field from playing together so long - it all adds up to me that Tamme is a key player.
He hasn't played much so far - he was injured at the end of training camp and I suspect he is not 100%. Establishing Welker as a threat was obviously a top Bronco priority - so I think Tamme seems marginalized as a player on the field for those aforementioned reasons. I am struck in interviews I've seen of him this year - just how confident he seems to be in his position on the team - he is not arrogant, but IMO he seems to represent himself as a guy who has certain knowledge of how he fits into this team.