Seriously, let's jump back to reality for a second. I love McCulley, and believe he will be the starter as a RS Sophomore, I do want him to see reps in the Idaho game assuming it's a blowout, the same can be said for the WKU game, but most people(myself included) don't understand how long it takes to be able to run a college offense. Trevor was the number one overall prospect in the country out of high school, he is also incredibly smart, Tua only played one half of the final game, while I am not going to diminish what he did, running an offense for an entire year and running an offense for one half+OT, when the other team has no scouting report on you are two very different things. Not to mention, both guys were 5 star prospects and early enrollees, so they had a five month head start on learning the playbook, McCulley was not an early enrollee, he has only been at IU since the start of summer. Barring injuries(which obviously isn't a guarantee), I do not want to see McCulley starting this season or even taking on any major role in the offense.
Penix is a phenomenal QB, and something else I feel the need to constantly point out, he masks an atrocious O-line, between his mobility, his quick release, and his willingness to take a hit he does all he can to hide the fact that our O-line has been pathetic over the past 9 games. I am sick of the jabs at Penix because he had one bad game in the season opener, against a ranked big ten team, on the road, coming off a major injury, oh yeah and this was everyone's first time dealing with crowd noise in two years. While I, like everyone didn't expect a performance that bad against Iowa, I think a lot of people thought that Penix in the OSU game was going to show up and that was extremely unrealistic given the circumstances. Give him a few games to kick the rust off and regain his confidence before you start talking about replacing him with Tuttle or McCulley.
While McCulley is a DT(really important given our O-line situation the last 3-4 years) and I believe he has a very bright future with the Hoosiers, he does not have experience going up against B1G defenses, being able to stand in and make those tough throws as your getting hit, something Penix had to do weekly last season, and if Iowa is any indicator, he'll have to do that again this year, not to mention the pressure that comes with being a starting QB at a power five school. I think a year learning the system and in the weight room, with no pressure to start or even be the backup is best for McCulley's development long term.