"I've just got to keep telling myself I've got to take it slow," Massaro said Wednesday in a conference call with reporters. "I've got to take it one day at a time, not get too far ahead of myself, because it does take time to get that muscle memory back.
"It's kind of a slow process. I'm kind of glad that I'm getting that out of the way now as opposed to during camp. So I think it's a good thing."
Massaro's Penn State career has been fraught with frustration. He missed the 2009 season after tearing the ACL in his right knee in the Blue-White Game the previous spring. After a productive 2010 season, he tore his left ACL early in drills last spring and sat out all of 2011.
The 6-foot-4, 260-pound Massaro, who has junior eligibility, said his knee right now is about 80 to 85 percent but noted that he's making progress toward the 100 percent mark. He said he has experienced "a fair amount of contact" thus far but that his daily workload is monitored by the coaches.
Admitting he is a little rusty, he said his knee still feels a little uncomfortable at times, partly from a brace that he must wear but hopes to shed in time for the start of the 2012 season. He said he's trying not to think about his knee when he's on the field.
"That's something that will slow me down if I start to think about it," he said. "There are times after I come out of a drill or a scrimmage or practice or whatever I'm doing, I'll say, 'Wow, that was a little scary.' But there's nothing that I think about while I'm in there."
Of course, there is a mental side to coming back, something with which he is accustomed following his return from his first ACL injury.
"There's definitely times when I feel my head gets in the way more than my knee does," he said. "There's other times where I can take a step back and say, 'Well, that part of it was mental, and the other part was definitely a little bit of rustiness on the part of my knee.'
"When I think back to last time when I came back from the last knee in camp, I was a little bit rusty then also. So I know it's something that I'm going to have to go through. It's just kind of an adjustment period. If I keep my nose to the grindstone and take it one day at a time, I know it's going to turn out all right."
Massaro and his teammates on defense have a significant adjustment with Ted Roof taking over for Tom Bradley as defensive coordinator under new head coach Bill O'Brien. Roof spent the last three seasons in the same position at Auburn, including the Tigers' 2010 BCS championship team.
"He's a really smart guy," Massaro said. "Every scheme that we put in, he tells us the strengths and weaknesses. That's all stuff we need to know. Each position gets a chance to learn the other position's responsibilities so we're all on the same page."
Massaro said the new terminology instituted by Roof "is kind of like learning a new language" but that communication among the defensive players is improving.
Massaro has a comfort level in that his position coach, defensive line coach Larry Johnson, was one of two members of Joe Paterno's staff to be retained by O'Brien.
"I don't know if it gets any better than coach Johnson," he said. "He's been a big help through all my ACLs. He's seen the pain that I've gone through and all the hard work that I've put in, and he's been a tremendous help. I can't say enough about what he's done."
Contact Joe Juliano at 215-854-4494 or email@example.com or follow on Twitter @joejulesinq