"Right now, we're still looking to see who the starters will be," Casteel said. "We're competing every day. Because a kid maybe started last year or whatnot (doesn't matter) -- our whole deal is we're trying to be a year better."
"Nothing has really been set. I know you may not want to believe that, but believe me, we go in and watch every rep and evaluate everything these kids do, and that's where we're at with that."
That idea differs from the general perception that most of the starters will be the same as they were a season ago. While nothing that has been seen in scrimmages so far shows any significant alterations to the first-team defense, Casteel's comments may mean that reserves coming up through the ranks are improving steadily.
"From our standpoint, the more kids that we can have an opportunity to play -- and we would like to play with a core of about 20 or 21 guys -- the better off we will be," he said. "The kids will dictate that, in their ability to make plays in practice and do what we ask of them. Every day (of practice) will determine how many guys we will play in the rotation."
The defensive coordinator singled out Zac Cooper's performance at the Sam linebacker position and Joshua Taylor's play along the defensive line as signs of quality depth in certain areas of the second-team defense.
Adding the play of some impressive newcomers, such as Jonathan Scott and Pat Miller, to the performances of more established backups like Cooper and Taylor, means that there is still plenty of time for the depth chart to shuffle somewhat between now and the season-opener against Liberty.
"Right now that clock is still ticking," Casteel said. "We are still a way's off from that first ball game. The kids are still being evaluated and still being coached. We have some talented younger players and a nice group of kids. It's our job to get them running in the right direction."
Indeed, the West Virginia defensive staff will hope that the continuity that exists this season -- both in terms of having a second straight season with the same group of position coaches and having an abundance of returning players with at least one year's experience under their belts -- can help the defense avoid the slow start that plagued last year's team.
"We've tried to look at some of the things we struggled with early (last) year," Casteel said. "Whether that be assignment football, paying attention to detail or being able to be consistent on third downs, we had to do a better job. Those are the things we had some trouble with."
"I liked the way our kids responded as the year went on, but what we want from them now is to be a year better and start being consistent from the first snap."
Of course, it helps Casteel, who doubles as the Mountaineer linebackers coach, to have the lynchpin of the defense returning after spending last season on the sidelines due to injury.
"You take a kid like Reed Williams out of the defense -- he is the heart and soul of the group and he has a knack for being able to make great plays," he said.
"The only thing that is settled right now is that No. 47 is in the middle."
While Casteel continually emphasized how early it is and that there is much work to be done in terms of bringing a consistent quality of play to the table, he said he was largely pleased with how his players have performed in camp.
"Our kids have given great effort for the most part," he said. "They are banged up. It's been a pretty physical camp and they've responded. But we're trying to work on being a consistent group, play in and play out. At this point, we're not."
"They're getting better every day. We have good leadership and if they continue to progress the way they have been, we'll be okay."