Penn State then-sophomore quarterback Christian Hackenberg (14) during a game against OSU on Oct. 25 in State College, Pa. Lynch ran for 38 total yards in OSU’s 31-24 double-overtime win. Credit: Lantern File Photo

Penn State then-sophomore quarterback Christian Hackenberg (14) during a game against OSU on Oct. 25 in State College, Pa. Lynch ran for 38 total yards in OSU’s 31-24 double-overtime win. Credit: Lantern File Photo

Location: State College, Pennsylvania

2014 record: 7-6

Head coach: James Franklin (second year, 10-7)

2015 record so far: 3-1

Record vs. OSU since 2005: 3-7

What’s happened so far in 2015: Coming off its first bowl appearance since January 2012, Penn State’s season began with an upset. Stunned on the road by losing to Temple for the first time in 74 years, the Nittany Lions dropped their season opener 27-10. They were able to bounce back in their home opener by taking care of the Buffalo Bulls, 27-14. The following two weeks, the Nittany Lions beat Rutgers 28-3 and San Diego State 37-21, and they now sit at 3-1 on the season.

Key offensive player: Before the season, junior quarterback Christian Hackenberg was projected to be one of the top picks in next year’s draft. After recent struggles, however, specifically the loss at Temple, his stock has fallen significantly. Still, he remains one of the best quarterbacks in the conference, and the key to PSU’s overall success. At 6-foot-4 and 228 pounds, Hackenberg is a prototypical pro-style quarterback — a rarity in college football — and can complete any pass. Through four games, Hackenberg has thrown for 668 yards, four touchdowns and two interceptions, and is second on Penn State’s all-time career passing list with 6,486 career passing yards.

Key defensive player: After moving from defensive end to defensive tackle last season, senior Anthony Zettel made PSU’s top position group even better. His combination of speed and power can overwhelm interior linemen, placing him among the elite defensive tackles in the conference. Last season, he registered 17 tackles for loss, which was second in the Big Ten behind Ohio State junior defensive end Joey Bosa. Through four games, the West Branch, Michigan, native has racked up 19 tackles, 2.5 tackles for loss and half a sack.

Weaknesses: Nothing can overshadow the holes in PSU’s roster. Losing its best linebacker, last season’s second-leading tackler Nyeem Wartman-White, for the season was a huge blow for the front seven. As the quarterback of the defense, he was extremely effective in defensive coordinator Ben Shoop’s scheme and can’t be adequately replaced. For a team lacking quality depth, the Nittany Lions can’t afford to take these hits, but they have. And the injuries are piling up. Both of their top running backs and safeties are sidelined, and redshirt sophomore tackle Andrew Nelson is dealing with a leg injury, creating a “next man up” mentality.