Having inherited a group that finished third in total defense during the 2023 season, Penn State football defensive coordinator Tom Allen has kept many of the central themes from the Manny Diaz era intact while implementing his own wrinkles and teaching methods.

Providing a stark contrast from Diaz, Allen came to Happy Valley with a milder personality that emphasizes teaching players the ins and outs of his defense. Having started at safety for Diaz in his sophomore and junior seasons, Jaylen Reed enters his senior year primed to start for Allen and has taken note of some differences between the two coordinators.

“Coach Manny, he was a real fired-up type of coach,” Reed said. “Coach Allen, he’s more teaching you the ins and outs.”

In the film room, Reed noted the approach Allen takes to breaking down film with his players, challenging them to explain the thought process behind certain plays and why they attacked it one specific way.

“If he calls a play, he breaks the play down and asks me, why am I doing this and why did I blitz this certain way?” Reed said. “He does this a lot, and it helps because it expands our thinking in football terms.”

Players such as Reed and starting cornerback Cam Miller have noted the overall philosophy under Allen remains largely the same as what Diaz ran at Penn State but some wrinkles may prove pivotal during his tenure.

“I feel like [Allen’s] and coach Diaz’s scheme is pretty similar, they run a lot of the same things,” Reed said. “One thing coach Allen does more is running a lot more nickel personnel. He brings more [defensive backs] on the field than coach Manny would.”

“It’s very similar to what Manny was doing,” Miller said. “We try to keep things simple so we can play fast.”

Under Allen, the Nittany Lions will transition from the traditional 4-3 defense with a SAM linebacker the team ran with Diaz to a 4-2-5 formation with a nickel defensive back under Allen. Reed has been among the contenders to start in the nickel role along with Zakee Wheatley, King Mack, and Zion Tracy.

Allen has continued to emphasize maximizing his roster and matching personnel with opposing offenses. Speaking specifically about the nickel position in his defense, Allen maintained he’s using spring practices to determine the handful of players he can use in this role.

“You have different uses for that position based on what we want to be able to do,” Allen said. “Who are the guys that can do the things we need them to do situationally?”

One other key cog in Allen’s defense is the Will linebacker, who, during Allen’s time as head coach at Indiana, would wear No. 44. During the 2023 season, Allen helped develop Will linebacker Aaron Casey into a first-team All-Big Ten selection.

“There’s a lot put on him to be the athlete of the group,” Allen said. “Here, you got a lot of different guys that can fill that role.”

“I don’t want to just be one. They should be able to have a lot of versatility in the room,” Allen added.

With a smile on his face, Allen has taken the same approach used in his film sessions to the practice field. According to Reed, Allen continues to show his players just how much he cares about them and their development.

“He really takes the time out during practice to pull us aside and have little conversations that we are not used to,” Reed said.

“It’s about relationships, and you got to build trust,” Allen said. “It doesn’t happen overnight and it takes time. It’s a huge part of my coaching philosophy.”