With such a young team, there may be years that more freshmen get in. You can't do that with every position but you can with some.
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I don't know if Entz's strategy is any different from Klieman's at all here. I can recall Klieman saying that if he thought that playing a true freshman gave them the best chance to win he was going to play him. Kobe Johnson's situation is almost identical to Bruce Anderson in 2015 when he played as a true frosh. That year they had King Frazier, Chase Morlock, Lance Dunn, and Darius Anderson so it's not like they needed help at RB but he was good enough to emerge as their primary kick returner and as a quality guy they could give 5-10 carries to when necessary. You could argue that had Klieman not done that Kobe Johnson would be redshirting this year since they'd still have Bruce Anderson as a 5th year senior bellcow RB. That does sound like a pretty nice option but ask yourself would they have beaten UNI in the 2015 quarters without Bruce's kick return TD??? It's a pretty interesting case study in this debate.
I think any coach would prefer to redshirt every player if they could but sometimes that doesn't necessarily help the team.
And even if you redshirt a kid there's a chance he gets hurt and misses another year anyway. I'm of the mindset if the kid can help us win now, play him.
And I wonder if he was being completely truthful whether or not Klieman regretted retaining Jabril Cox's redshirt in 2016. The story I've heard is that they didn't think he was mentally ready yet even though they already knew how physically gifted he was. I would guess that a healthy Jabril Cox would've came in pretty handy in that 2016 semi against JMU over a hobbled PGT or Matt Plank.