I just don't get all the consternation about inexperienced depth. It's the nature of college football that there is turnover at almost every position which leads to players with limited experience being backups, and in some cases starters.
The only positions with experienced depth on PSU's roster seem to be the OLine. And how experienced is Cousins, really. We know he's a talent, but he really doesn't seem to be as experienced as Wylie at LB, who has gone through 3+ years of practice and has game snaps as well.
Anyway, here are what I see as the most vulnerable positions, where an injury could derail the season, listed as the least depth, most risk, positions first, with less risk going down the list. Also taken into account is the fact that positions such as DE, DT, RB, CB and WR seem to be positions that the top backups regularly play often through the course of games and the season to keep starters fresh even without injurys where as the starters at positions such as QB and OL and are rarely replaced with the game still on the line.
QB. Inexperienced depth with Grunk and Smolik. QB seems like the biggest concern regarding depth. If Allar goes down with an injury a playoff berth and particularly playoff success would seem unlikely.
Safety.
An All American level player in Wheatley, but unproven players making up the 2nd starter and top backup with Lane, Mack and Belgrave-Shorter competing for the starting spot and to be the first Safety off the bench. With Toure as well competing as a 2nd year talent there is talent at the position, but an injury to Wheatley would seem to be a serious negative to the overall performance of the defense.
DE.
Only 1 returning starter (DDS) with no other DE having been in last year's DE rotation, although Fisher the likely 2nd starter is a mature player but with limited playing experience. Positive comments from the staff regarding the young DE's that will make up the remainder of the DE rotation (Harvey, Kemajou, Williams and Coleman), but an injury to either of the starters would force an inexperienced player into a starting DE role, and an injury to DDS would be a significant blow to the overall DE performance.
DT:
Similar to DE, only 1 returning DT starter (Durant) but the other projected starter (Ford) was playing a significant rotational role before his injury. Positive comments from the staff regarding the young DT's that will make up the remainder of the DT rotation (Gilliam, Wafle, Blanding and possibly White), but an injury to either of the starters, would force an inexperienced player into a starting DT role and an injury to pre-season All American Durant would likely take DT from a team strength to a position weakness.
WR.
The 3 transfer WR's all seem to be players that will likely start, although only Hudson has significant experience playing against B10 defenses. Behind those 3 Clifford is the only experienced backup and he doesn't seem to have the talent to stretch the field. There have been positive reports regarding both Denmark and Howard but they do not have the experience to be considered sure fire replacements as starting WR's in the event of injuries to the starter. And with many 3 WR sets even the projected starters are not sure bets to retain their starting roles if they do not live up to their projected playmaking roles.
LB.
With the tranfer Campbell having been a starter at NC joining Rojas and DeLuka PSU has 3 returning starting LB's for the base defense's 2 starting positions, although there will be times when the defense will play 3 LB's. The backups project to be Wylie who has competed to start in past years and is going into his 4th year in the program but has limited actual playing experienced due to injuries, Speca who was mentioned as a possible candidate to burn his redshirt last season if there are injuries and has gotten positive comments from the coaches. and Nelson who played as a backup last season and is going into his 3rd year at PSU. Additionally, there are a number of other young players (2nd year player Jackson, and true freshmen Tatsch, and Arrington) that have gotten positive comments from the coaches, and we've seen true freshmen play LB successfully in the past. An injury to one of the 3 starters would force a young player into a more promenent role but returning starter would still man the base 2 LB set.
TE
A seemingly deep position with Dinkins, Reynolds and Rappleyea all projecting to be stater capable, and the 3rd year Schlaffer as the 4th TE. Even with multiple TE sets it seems like an injury to one of the top TE's could be overcome, but losing Dinkins' blocking skills could negatively impact the running game. And an injury to Dinkins would put an inexperienced TE into the rotation for 2 TE sets.
RB.
A deep position with Singleton and Allen as co-starters, and the top 3 backups all being 2nd and 3rd year players, Wallace, Marting and Smith. But an injury to Singleton, for example, would likely put more carries per game to Allen until whoever emerges at RB3 gets more game experience and proves himself in pass protection and ball security.
CB.
A contender for deepest position. With Harris, Washington and Collins there seem sto be 3 top talented starters for 2 positions. Add in Woseley, Dixon, and Tracey (the starter at Lion) and it seems like a extremely talented and deep position, which is needed to keep the CB's fresh against teams with top passing offenses like both OSU's. It's also possible that another of the true freshmen, Joseph, Johnson and Thomas, may be ready for some snaps as they continue to practice.
Oline.
With Washington, Cousins, Shanahan, Birchmeier, Boyer and others as backups this seems like possibly the deepest position. An injury to an OT would put Donkoh back to OT, although an injury to Shelton would likely cause either Donkoh or Rucci to have to move to the left side. It's possible that the staff would rather have Washington replace Shelton. Inside, Cousins and/or Shanahan seem like very capable backups. But continuity on the OL is what makes an OL unit reach top performance so any disruption likely leads to some dropoff in performance.