"I am ready to go against a different defense besides ours," Castillo said and smiled.
Well, Florida State's offense will get that opportunity on Saturday, when the Seminoles open their regular-season at North Carolina. Kickoff is 8 p.m. and the game will be televised nationally by ABC.
The Tar Heels return eight starters from a unit that ranked ninth in the Atlantic Coast Conference and 108 nationally in total defense, allowing a whopping 452.4 yards per game last season.
In fact, UNC started a different lineup defensively every game last season. The Tar Heels had little or no pass rush and the talent level among the upper classmen is considered suspect other than defensive backs Dexter Reid and Michael Waddell.
Reid is the nation's top returning tackler, while Waddell has started a team-high 33 games despite suffering a broken leg late last year.
FSU's biggest concern this preseason, of course, has been its young offensive line.
The starters all are underclassmen and the second unit features three true freshman. The Seminoles' offense was dominated by the defense in the first three scrimmages but enjoyed welcomed success against the scout team in last Friday‘s final scrimmage.
The gritty but oft-injured Castillo has emerged as one of the group's inspirational leader.
"We've got a lot of preparation from two-a-days facing our defense," Castillo told The Territory following Saturday morning's light practice.
"There is no dropoff from our one and two defense. If there is, it's hardly at all, especially at the tackles position. We've got great defensive tackles and great ends. They sent a lot of blitzes at us. We have a great linebacking core. Coach Steele and Coach Andrews did a good job. We saw every look in the book. We should definitely be better. I don't think we will see a defense that played as good as ours during this two-a-days."
Castillo, who made his first career start last season against North Carolina, has been impressed by the Seminoles' freshman trio of John Frady, Mario Henderson and David Overmyer. Frady is Castillo's backup.
As expected, however, there also has been some difficult times as well for the newcomers.
"A couple of them are getting a little frustrated," Castillo admitted.
"When you come out of high school, they are used to being the big dog, being the best on their team, best in their area, best in the state. When they here, they are not used to seeing… the speed, especially. How big they are, how quick they are, how strong they are. In high school, you either have a real big guy or a smaller quick guy. You don't have both.
"When you get here, you have defensive tackles who run like the wind. It's very hard. If you don't have good technique, or make the correct first step, they are by you. These guys are not used to getting beat. They have to humble themselves and realize it's gong to take them some time to get used to this level. But they will get there."
Castillo will also have his hands full against the Tar Heels. Defensive tackles Donti Coats (300 pounds) and Chase Page should provide a stern challenge. Page is a former offensive guard who became a top producer in the middle last season, registering 48 tackles and 4.5 tackles for loss.
"My first start was against North Carolina, so I know what they are capable of," Castillo said.
"They have a good defense. They are big up front. They have a lot of good run stoppers. That nose guard (Coats) is a big boy. So, this is going to be a good challenge for us. But, like I said, after going up against our (defense), we will be ready for anything."