Farrell's take: I was concerned that Washington, a former five-star defensive end, wasn't big or strong enough to be consistent at defensive tackle. In fact if you told me he'd be a defensive tackle in college based on his high school frame I would have been puzzled. Johnson, a three-star out of high school, was a hoops guy more than a football guy. But that athleticism and footwork has helped.

The skinny: Robinson was a five-star out of Fort Worth (Texas) Arlington Heights and was rated as the fourth-best prospect at his position in the 2013 class. In late December before National Signing Day, Robinson said his Texas commitment was "as solid as a rock." Only weeks later, the five-star prospect took an official visit to Alabama and he flipped his pledge to the Crimson Tide shortly after that trip.

Season overview: Robinson has 39 tackles (seven for loss) including three sacks. He also has one fumble recovery and eight quarterback hurries.

Farrell's take: Some people think Robinson has slipped a little while others still see the former five-star's amazing potential. To me, he has improved as the season progressed and his ability to make plays in space, get after the quarterback and anticipate the play makes him the safest bet at defensive tackle. He was a man among boys in high school and at times you can see that at the college level, especially against top competition.

The skinny: The Waco, Texas, four-star prospect was rated as the No. 12 defensive tackle and No. 168 overall in the 2013 class. Early in his senior season, Billings had his choices narrowed to Baylor, Texas, SMU, TCU and Mississippi State and he wanted to make an early commitment. But Billings decided to hold off and a day before National Signing Day he picked Baylor over the Longhorns and Horned Frogs.

Season overview: Billings only has 33 tackles this season but an impressive 13.5 tackles for loss and 4.5 sacks. He also has a forced fumble and Baylor allows just 3.6 yards per rush and 27.9 points per game.

Farrell's take: Billings is a monster in the middle and one of the strongest kids I've ever scouted. That power has allowed him to push the pocket and make numerous plays in the backfield like he did in high school. His burst to the ballcarrier is what has been the biggest surprise, something he didn't show as much out of high school as he was a bit more stiff. He could be the home-run defensive tackle pick of this draft for a team wanting someone to dominate blockers.

Farrell's take: Collins, a former three-star, is a gasher who does his best work shooting the gap and making plays in the backfield. His high-end ability to get after the quarterback makes up for some concerns about him being a run-stuffer. We moved Nkemdiche back to defensive tackle from defensive end but we feel he could play either. The former No. 1 overall recruit on Rivals.com has all the athletic ability you want, but consistency is an issue. He'll dominate and have a huge game and then struggle the next. His injury didn't help and let's hope he never sees another carry as a running back again.

The skinny: The Houston, Miss., recruit was rated as a five-star and the second-best strong-side defensive end in the 2013 class. Two days after working out at Mississippi State's summer camp, Jones committed to the Bulldogs. Jones showed significant interest in Ole Miss close to National Signing Day but decided to stick with Mississippi State.

Season overview: Jones has 39 tackles (7.5 for loss) including 2.5 sacks so far this season. He has five quarterback hurries.

Farrell's take: Many feel Jones is a one-trick pony at defensive tackle who has trouble at the point of attack and uses his length and athletic ability more than technique to make plays. The former five-star has a high ceiling and could be an end in a 3-4 defense, but he might have bulked up too much and could be playing a bit out of position based on what we saw as a pass rusher coming out of high school.

The skinny: The four-star from West Branch (Mich.) Ogemaw Heights was rated as the sixth-best strong-side defensive end and No. 65 overall in the 2011 class. In a somewhat surprising move, Zettel picked Penn State over Michigan and Michigan State a few days after Christmas following a vacation to the Dominican Republic.

Season overview: Zettel has 43 tackles (10 for loss) with three sacks and a fumble recovery so far this season. Penn State allows 3.8 yards per rush.

Farrell's take: Zettel, who has an amazing motor, has been passed by Johnson as a defensive tackle prospect for NFL teams but is more scheme-versatile. That being said, he's very good at getting after the quarterback, but there are concerns about his size and ability against the run and handling double teams.

Farrell's take: Day, a former four-star, is a pure nose to us and he can be very disruptive at the point of attack, push the pocket and shed blocks to make plays against the run. But he has also shown a lack of overall athleticism at the position in space, which has dropped his stock a bit compared to other more athletic players at his position. He's had a better year than last year, but yet it's such a deep and athletic year at DT he's going to likely slide to second or third round based on ceiling. Vanderdoes is simply an injury issue when it comes to the former five-star's fall.