But how many of them have eligibility to continue playing? And, more importantly, how many of those Juniors are red-shirt Sophomores?
I'm actually not being pedantic or snarky, roster management is messy, but a lot of "how much older/younger is the team now and is it going to get next year" is masked with the stat "X number of juniors and seniors." A lot of the time (and is true in this case), red-shirt sophomores are included in that stat line - even though many of them will still be playing in 3 years (three years on campus (juniors), but one year redshirting (RS Soph).
If you're evaluating the current team in terms of age and experience, the number of juniors and seniors is a good line to use.
If you're evaluating how much of a drop off in age and experience the team is going to experience in the following two seasons, it's better to use something like "how many players will run out eligibility in the next two seasons?"
Now, for these numbers I'm only using scholarship players who were on the roster at the start of fall camp (it was the roster I could find in the easiest format to sort and count).
This year, we have 53 Juniors and Seniors (older and experienced, yay!)
We will have 41 players running out of eligibility at the end of 2017.
In 2017, we will have 50 Juniors and Seniors (again, older and experienced, yay!)
In 2017, we will have 39 players running out of eligibility at the end of 2018.
In 2018, we will have 42 Juniors and Seniors (younger, but still half the roster is "upperclassmen")
In 2018, we will have 35 players running out of eligibility at the end of 2019.
This is what proper class balance looks like in a P5 program, and it is truly a huge (and unheralded) success of HCMM to get us to this point in only 4 seasons. Unless we get a glut of guys leaving early for the NFL draft (a good problem to have) or a glut of injuries in one class (bad problem to have), at least half the roster should always be made up of guys who are in at least their 3rd year of college, i.e. "juniors" and older.