Asked to name a player who may be flying a bit under the radar for whom he expects big things this season, Castillo points to defensive tackle Brodrick Bunkley.
"I'm really excited about Bunk," Castillo said. "This is the kind of system where he came from, where he can attack and just have fun. We're going to have some fun. I hope Bunk is out there listening to this, we're going to have some fun now."
The biggest reason behind Castillo's optimism for Bunkley is the transition spearheaded by new defensive line coach Jim Washburn. For the past few seasons, the Eagles' defensive tackles have been utilized in a role that downplayed their playmaking ability. Often times, their job was to occupy blockers at the line of scrimmage, allowing the linebackers to freely flow to the football. Under Washburn and his noted "wide-nine" technique, the defensive linemen will be much more attack-minded. And that's something that could play directly into Bunkley's strengths.
At Florida State, Bunkley played a similar style. The results? In his senior season, Bunkley totaled 25 tackles for loss, the second-best in the entire country and the best for an interior lineman. But in his five seasons with the Eagles, Bunkley has only accumulated 16 total tackles for loss, thanks, at least in part, to a scheme that asked him to read and react more.
In all, Castillo feels very good about the defensive tackle position. Including Bunkley, there are four players who should all be significant contributors.
"We're excited about our tackle situation," Castillo said. "Mike Patterson, good football player. (Antonio) Dixon played really well last year. (Trevor) Laws is coming off a marriage, so you know he's ready to come to work."
Moving from the defensive position closest to the quarterback to the last line of defense, Castillo also shed some light on the safety position. When Jaiquawn Jarrett was drafted in the second round, the presumption was that he would have an opportunity to start as rookie - though he'd surely face stiff competition from Kurt Coleman. But with the work stoppage still ongoing, will Jarrett have enough of a chance to learn the defense?
"I think what's important for people to understand is that some of the coverages that they use in colleges are the same as the ones that we use here," Castillo said. "For example, two deep, cover two at Temple is just like cover two in Philadelphia. So is it hard? Yeah, but it's not as hard as people think.
"I think what's important is when you have a player who's good enough athletically and physically, that it's the coaches' job to prepare the player. I think that's very important for us. That's the way we look at it, make whoever the best players are, it doesn't matter whether they're rookies or five or six-year guys, it's our job to prepare them and have them ready to play."
Castillo also warned not to pigeonhole Jarrett as nothing more than a hard-hitting safety and Allen as the roaming playmaker.
"I know Nate would think he can knock your block off, and Jarrett thinks he can be the same kind of rangy player," said Castillo. "I think the thing you want to do is have two guys who can do both things, and we feel like we have not just those two, we have a few other guys who can also do that. So there's going to be some competition back there."
For now, Castillo will continue to hit the game tape with his assistants, preparing for what will be his first season calling plays. And when time comes for Castillo to finally be able to work with the players on the field, he expects to hit the ground running.
"I think the intelligence factor (for our players) will help us a lot," he said. "But then as coaches too, we have to do a good job of teaching concepts and getting the concepts to our players."