The other tight ends on the roster are Kyle Griffits (although RBs coach Reno Mahe says he's more of a fullback), Troy Hinds and Nate Sampson.
Bushman, a returned missionary who is also playing baseball, can't talk to reporters until after the first game this fall, due to BYU's rules regarding "newcomers" talking to the media.
Mangum said it is taking some time to get adjusted to the new tight ends and receivers in camp.
"I think every day gets better," he said Wednesday. "The key is just reps, but especially reps at full speed, going at a defense. You can throw routes on air. That stuff is important. But you gotta be able to translate that to game speed, going against a live defense. So I thought today was good for us, being able to go against our starting D, with down and distance. It gives us a good feel with where we are at. So I think we just have to keep that up. I think we are getting better. Still have a ways to go, but I like the direction we are headed."
Mangum said he's learned a lot from Detmer already.
"Last year was good, being on the headsets every game, listening to his calls, listen to what he likes," Mangum said. "Then to spend every day with him in the meeting room has been good. He's a great coach, a great teacher. He really helps you understand things. I am loving it. I am really excited to be working with him and learning every day.
It is a just a nice feeling knowing you can go to the coach's room any time and be able to watch film with them, ask questions. He does a good job of helping me out and helping all of us out. It is a blessing, for sure."
Head coach Kalani Sitake said Wednesday the offense is way ahead of where it was at this time last year, thanks to familiarity with the system and a seasoned offensive line that has to replace just one starter, left tackle Andrew Eide.
"Our O line is so much further along than we've been, and that's [good]," Sitake said. "They have a lot of confidence because they are bigger. We have a little bit of depth. Obviously we want to create more depth. But those guys are bigger and stronger and they are playing with a lot more confidence.
The defense is bringing a lot of different looks at them, and they are doing OK with it. I think every coach will tell you the defense comes a lot faster and is easier to install than the offense, but we have a lot of experience with those four guys returning on the O line, and they've done a great job leading the rest, so the key is to get the second group ready to roll and make sure we fill in that left tackle spot. We have moved Thomas Shoaf over [to left tackle], so we are competing for the right tackle spot. We are also competing for all the other spots."
Of course, center Tejan Koroma is the OL's anchor, and the senior from Allen, Texas, will contend for All-America honors in 2017.
"Tejan is amazing to have in front of you. Just having him there gives you a sense of relief, knowing that he is an animal and is fighting like crazy in there. He is smart, too. He knows how to pick up blitzes and everything," Mangum said.
"I think he and I, the more we play together, the more in synch we are. He's doing a great job and the O line is doing a good job of taking the mastery of the offense to another level.
The new guys coming up are doing a good job as well. Kiefer [Longson], and [Chandon] Herring and [Austin] Chambers. We have a lot of good new guys coming up. Tejan is doing a good job of leading those guys. He is a senior now. He's a veteran, a proven guy. So it is a good feeling having those guys in front of you."