The two reserve tight ends who have stood out in training camp to me are Tony Moeaki and Greg Scruggs.
With Zach Miller sidelined due to a concussion, Moeaki has helped fill the void as a pass catcher, making several receptions, including a couple for touchdowns. The Wheaton native had a great rookie season with the Chiefs in 2010, but his career has been derailed by injuries.
Scruggs is playing TE as a former defensive end and has taken the most steps according to Jay Cutler, who was quoted in the story. Miller is still sidelined with a concussion which is allowing others to step up in his place. Moeaki obviously has the most experience at the position and would seem to be next in line if Miller remains out.