STATE COLLEGE, Pa. - As James Franklin previewed spring practice Tuesday afternoon, the Penn State coach voiced optimism about many changes, including several position shifts and a stronger, more experienced offensive line to better protect quarterback Christian Hackenberg.

"The fact that we're going to have two deep of scholarship players is exciting," Franklin said. "There's nobody that is happier about this group returning and the strides they've made than Mr. and Mrs. Hackenberg."

The quarterback took much criticism in his sophomore season, and in retrospect, Franklin said it upset him.

"Last year, Christian spent most of his time solving problems, running from problems, taking a lot of criticism, which I'm really, really defensive about," Franklin said. "To be honest with you, looking back at it, [I'm] a little angry that he faced some of the criticism he did. I don't know if it was fair, just, or realistic."

Franklin opened the news conference by citing statistics about added muscle during offseason workouts. But the coach was also realistic, acknowledging the challenges facing the team as it attempts to improve on a somewhat underwhelming 7-6 season.

The biggest challenge: replacing star middle linebacker Mike Hull. Franklin said Nyeem Wartman, Gary Wooten, and Ben Kline could compete for the job.

Franklin also is working to strengthen the offensive line. He responded to a question about the opening at left tackle by praising Albert Hall, who walked on his freshman year and saw a fair amount of playing time last season.

"The guy has done everything we've asked him to do," Franklin said. "He moves well, is athletic. We're excited about the competition there."

The offensive tackle competition also includes Chance Sorrell, Franklin said, as well as two early enrollees, Sterling Jenkins and junior college transfer Paris Palmer.

On the defensive side, Franklin singled out Malvern Prep product Carl Nassib, an end who had a "sneaky, quiet, really successful year" in 2014.

Among the position changes, freshman Amani Oruwariye will move with Jordan Lucas from cornerback to safety, Jack Haffner will go from running back to linebacker, and Adam Geiger will move from running back to safety.

Haffner and Geiger should be "special-team terrors," Franklin said.

And with Sam Ficken gone, Chris Gulla will focus solely on kicking, not punting.

Franklin said he and his staff have discussed opening the April 18 Blue-White game with a kicking competition and holding a punting contest at the half.

Although he is proud of the strides the team has made, Franklin seemed focused on making a long-term impact as well.

"Joe [Paterno] was here 62 years and I've been here 62 weeks," Franklin said. "I've got a long way to go."