This has been an Achilles heel for the Ohio State defense the past two weeks. The Buckeyes are in the middle of the pack for the season with a 38.5 percent conversion rate that ranks 53rd in the nation and No. 6 in the Big Ten, but Purdue and Indiana combined to convert 19 of 35 of their chances (54 percent) the past two weeks.
"We've got to make a few more plays," OSU head coach Luke Fickell said. "When you break those stats down, that is the last two weeks where we've been probably poorest, and sometimes when you just look at third downs in general, if you're good on third down, it's probably because you had a lot more third-and-7 to 10s than you did from third-and-3 to 5s."
The Penn State offense is 96th in the country in third-down conversions (36.5 percent).
2. What will DeVier Posey do in his season debut?
Senior Day is also season debut time for Posey, a former five-star recruit who has seen his final year in Columbus delayed by a pair of NCAA suspensions.
Although he might be rusty after so much time on the bench, Posey's experience is unparalleled in the Ohio State receivers room as the next-oldest scholarship player is third-year sophomore Chris Fields.
Posey was an honorable mention All-Big Ten selection last season and has 25 career starts. He enters the game with 124 catches for 1,793 yards and 16 touchdowns, and his teammates hope his presence can dissuade Penn State from overloading the box with defenders to stop the run.
3. How will the fill-ins fare?
Ohio State could find itself without two of its best defensive players Saturday. Fickell ruled linebacker Andrew Sweat out for the contest because of a head injury and indicated lineman Johnathan Hankins is questionable thanks to a knee problem.
Ryan Shazier is set to step into Sweat's shoes at Will linebacker while Hankins' likely replacement would be Michael Bennett. Both are true freshmen. Bennett has been a consistent part of the defensive line rotation for much of the season and already has three sacks. Shazier has three sacks as well and two forced fumbles.
The Buckeyes might also be down a man on the offensive side of the ball, but right tackle J.B. Shugarts reportedly was able to practice Tuesday so his status remains uncertain. If he cannot go, Jack Mewhort is expected to play right tackle with Corey Linsley at right guard.
4. Which quarterback will make the fewest mistakes?
Many recent meetings in this series have been heavily influenced by turnovers from the quarterback position. The Nittany Lions were leading last season before Matt McGloin threw a pair of interceptions that were returned for touchdowns, and the turning point of the Buckeyes' 13-6 loss in 2008 was a fumble by OSU quarterback Terrelle Pryor in the fourth quarter.
Penn State's 2005 upset win in 2005 included a pair of costly miscues by Troy Smith, one that led to a 1-yard touchdown drive and another that ended the last Ohio State possession in a 17-10 game, and the Buckeyes put away a closer-than-it-looked 2006 contest with a pair of interceptions of Anthony Morelli in the closing minutes.
Entering this game, Buckeye freshman Braxton Miller has thrown three interceptions and lost three fumbles. McGloin, who spent much of the year splitting time with Rob Bolden, has thrown three interceptions and lost one fumble.
5. Can the Penn State offense outscore the Ohio State defense?
This might sound like an odd question, but that has been a struggle for the Nittany Lions in Ohio Stadium since joining the Big Ten in 1993.
Ohio State has scored eight defensive touchdowns – seven on interception returns and one on a fumble return – while giving up the same total. Last year saw the first Penn State touchdown passes at Ohio Stadium since the early 1960s, but the Buckeyes struck back with a pair of pick-sixes to even the score again.