Only two months ago, Northwestern’s newest starting defensive lineman was merely the backup’s backup, the true freshman who didn’t even get his own mug in the team media guide.

But a slew of season-ending injuries has given Thomas Derricks more promotions in five weeks than most players hope for by the time they’re fifth-year seniors. Sophomore Matt Anderson suffered a sprained knee against Penn State, an injury that will likely sideline him for the season. This opens the door for Derricks at left defensive tackle.

“I always dreamed of having the opportunity to start,” Derricks said. “My dream has come true now. Unfortunately, we lost two guys, and I’m not saying I’m glad they got hurt. To me, it’s just, ‘Here’s my opportunity.'”

Anderson was listed as the third-string right tackle heading into the season. But he took over for starter Pete Chapman when the junior developed a blood clot in his leg after just one game. A week later, the line took another hit when senior defensive end Pete Konopka developed back problems.

All of NU’s injuries have forced coach Randy Walker to play an inexperienced lineup in the trenches, further weakening a defense that was a question mark heading into the season. Walker will now start a pair of freshmen in the interior, who will be book-ended by tackle-turned-end Salem Simon and former linebacker Napoleon Harris.

“We’re thin and we’re getting close to not having enough to play with,” Walker said. “I’m not going to say it’s not a concern, because it is. Hopefully we stay healthy the rest of the way.”

Walker said he is confident Derricks will be able to step into the starting lineup. And although the freshman had jitters earlier in the season, Derricks said he’s ready.

“This is our seventh game now and I know what it looks like out there,” he said. “It’s time for me to grow up.”

close call: Although he was held out of contact drills, wideout Sam Simmons practiced with the team on Tuesday. Simmons dove to the ground to catch a Zak Kustok pass on Saturday and felt a Nittany Lions defender collapse on top of him.

“I reached my hand up and I felt it, and I knew it felt kind of funny,” Simmons said. “I was praying it wasn’t my collarbone again, something that could’ve been the end of my season.”

The hit was similar to the one that broke his collarbone in 1999. Simmons said he lay on the ground for several moments fearing the worst.

This ailment was only the latest in a long line of injuries Simmons has sustained this season.

He fractured his finger against Duke on Sept. 22 and jammed his right shoulder on Oct. 13 against Minnesota. Although he said he’s still sore from both games, the senior expects to recover in time to play Purdue.

Walker said he didn’t want to keep Simmons out of practice this week, as he did after the Duke game. That extra time off made Simmons rusty for NU’s next two games.

“I have a good feeling about Sam,” Walker said. “Sam has invested a whole lot in this season. I think he’s going to find a way to get through it.”

Not-so-fair catch: Two questionable calls may have cost the Cats dearly in Saturday’s 38-35 loss.

Penn State’s Bruce Branch appeared to signal for a fair catch on a 50-yard J.J. Standring punt in the second quarter. But when the ball fell into his hands, Branch took off for a 17-yard return. The sprint immediately elicited boos from the crowd. Everyone at Ryan Field except for the referees seemed to pick up on Branch’s pre-catch wave, including NU defenders, who relaxed after his signal.

Six plays later, the Nittany Lions scored to tie the game at 7.

The controversy continued in the game’s final seconds, when Cats wideout Jon Schweighardt caught a 5-yard pass from Kustok along the left sideline. Although tape showed Schweighardt crossing the sideline with the ball, referees ruled him in bounds and the clock kept ticking. NU used a timeout to stop the clock, but one play later, time ran out on a last-ditch scoring attempt.

Walker said he spoke with Big Ten Director of Football Officials Dave Parry about the calls in their weekly chat. He would not elaborate on the details of the conversation.

INCHES TO GO: Walker said he doesn’t expect redshirt-freshman Jarvis Adams to return this season after he sprained his ankle against Minnesota. The backup safety is eighth on the team with 29 total tackles. … Penn State had the worst turnover ratio in the conference before Saturday’s game, but the Nittany Lions didn’t turn the ball over once against the Cats. … NU offensive coordinator Kevin Wilson celebrated his 40th birthday on Tuesday.