With the 2021 Penn State football season coming into view, Blue White Illustrated is using Pro Football Focus ratings to rank the 25 best players on Penn State's roster. The rankings are based on last season's PFF ratings, and the rankings only include players who played at least 100 snaps least season on offense or defense — with the exception of specialists. In case you missed it, catch up with Nos. 16-25 in the rankings, here:

Ranking Penn State's best 25 players ahead of '21 by PFF rating: Nos. 21-25

Ranking Penn State's best 25 players ahead of '21 by PFF rating: Nos. 16-20

PFF Defense Grade: 67.2

Tariq Castro-Fields had a frustrating 2020 season, as he struggled with injuries and appeared in only Penn State's first three games of the season. Still, that gave him enough snaps to qualify for our list. He improved upon a subpar 62.7 grade in 2019, but was unable to replicate his 77.2 grade back in 2019, which he'll look to do in his fifth and final season after opting to return for one more go.

PFF Defense Grade: 67.7

Micah Parsons' choice to opt-out of the season cleared things out for Ellis Brooks to walk into a starting role for the first time in his career, and he handled it reasonably well, posting a 67.7 grade. He struggled in pass coverage, where he received a grade of just 55.3, but was an excellent tackler and a solid pass rusher when given the chance. He'll look to take another step in his second year as a starter in 2021.

PFF Offense Grade: 68.3

Caedan Wallace is the second Penn State offensive lineman to appear on our list, and he earns a place after producing a remarkably well-rounded effort in his redshirt freshman season. He earned similar grades as a pass blocker and run blocker, showcasing an ability in all phases of the game that Penn State will hope to lean on in 2021 and beyond.

PFF Defense Grade: 69.1

Adisa Isaac has a big task ahead of him as he figures to earn plenty more snaps following the departure of Odafe Oweh and Shaka Toney, but the results last season indicate he's up for the task. He got to the quarterback twice on 86 pass rush reps, and also earned a 74.0 grade as a tackler.

PFF Defense Grade: 69.6

Joey Porter Jr. stepped right into a starting role following his redshirt season in 2019, and the results were fantastic. He was among the best-tackling corners in the nation, with a grade of 85.8. He was also decent in pass coverage and defended the run well. He'll face some competition at corner after the Nittany Lions loaded up on depth over the offseason, but he's an exciting option no matter his role.

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