WEST LAFAYETTE, Ind. — Purdue didn’t expect to be in desperation mode halfway through the Big Ten schedule.

The Boilermakers entered the season with experience on offense and star power on defense in defensive tackle Kawann Short and cornerback Ricardo Allen. They were expected to take advantage of a weakened Big Ten Leaders Division with both Ohio State and Penn State ineligible for postseason play because of NCAA rules violations.

Purdue (3-5, 0-4) has lost its first four conference games, including three by double digits. The key is to stop the bleeding before the Boilermakers are out of the bowl picture, starting today at home against surprising Penn State

(5-3, 3-1). Purdue must win three of its final four games to become bowl eligible.

Things have gotten so bad that Purdue Athletic Director Morgan Burke put out a statement early in the week.

“Our student-athletes, alumni, fans, coaching staff and administration all expect to see the program move forward and take a step up the postseason ladder,” Burke said. “Currently, our performance has kept us from reaching our goals. But we have a third of the season left to play, and our focus is to achieve that consistency over the remaining four games. We need to press forward, converting potential into results and having fun playing Boilermaker football.”

Coach Danny Hope expects his team to rally, given the urgency of the situation. Last week’s 44-28 loss to Minnesota put a great deal of pressure on Hope and the team for the rest of the season.

“I know they were embarrassed by their performance this past Saturday, and I expect to see them bounce back with a real commitment, on a real mission,” Hope said.

Hope has benched quarterback Caleb TerBush and replaced him with Robert Marve, a sixth-year senior who has torn his left ACL three times.

The strong-armed, talented Marve is more of a risk-taker than TerBush, and he has been much more effective. TerBush completed 58 percent of his passes and has a 119 passer rating with 11 touchdowns and eight interceptions while Marve has completed 65 percent and has a 136.9 passer rating with six touchdowns and two interceptions.

Hope made the switch after TerBush completed 5 of 18 passes against Minnesota. Purdue trailed  44-7 before Marve stepped in and rallied the team.

“Caleb and those around him at times did not play as well as we’d have liked for them to play,” Hope said. “As a result, Caleb didn’t play as well as he has or as well as we expected him to. We put Robert Marve in the ballgame, he played very well, completed a bunch of passes. I don’t think he had any true incomplete passes. He had  some drops and a batted ball, but had great quarterback stats and was able to generate some drives. He was very, very accurate with his passes.”

Marve started the season opener against Eastern Kentucky because TerBush, the original starter, was suspended for a game. Marve passed for 295 yards and three touchdowns, but Hope gave TerBush his job back after the suspension, and he remained the starter until now.

Marve expects to play well.

“I plan on having a lot of fun, to be honest with you,” he said.

While Purdue’s failure is unexpected, so is Penn State’s success. After the penalties the NCAA handed down after the Jerry Sandusky scandal, many Penn State players transferred. Those who stayed knew the program was banned from postseason play.

The Nittany Lions stayed focused and have played inspired football under Bill O’Brien. Even with last week’s 35-23 loss to Ohio State, Penn State has had a better season than many expected.

“We have a resilient bunch of players, and like I’ve said every single week, it’s led by a fantastic senior class, a bunch of guys that have a passion for playing football for Penn State, for going to school here at Penn State, and they realize that there are only four games left,” O’Brien said.

Penn State quarterback Matt McGloin has been one of the best quarterbacks in the Big Ten this season. He has passed for 2,115 yards this season. McGloin’s top target, Allen Robinson, has 52 catches for 631 yards and eight touchdowns. Zach Zwinak leads the running game with 411 yards.

Penn State will face a Purdue defense that has struggled. The Boilermakers rank 10th out of 12 teams in scoring defense, surrendering nearly 30 points per game, and 11th in total defense, allowing 408.4 yards per game.

Short injured his right ankle last weekend but Hope expects him to play.

He leads the Boilermakers with four sacks and nine tackles for loss. The Boilermakers hope Short and the defense improve so the bad vibes circulating around Hope and the program can go away.

“I’ve got Coach Hope’s back, whatever happens,” Marve said. “I’m not worried about that, I’m worried about winning.”