Probably the biggest question mark going into last season in Wade Phillips new 3-4 defense, the defensive line, became a strength midway through the season. Antonio Smith, J.J. Watt, and Shaun Cody all had to adapt to new positions from what they played the season before, but by the end of the season they were playing at a high level and definitely exceeded expectations. The trio of Smith, Watt, and Cody started all 16 games, but other players did see a decent amount of playing time with the way the Texans rotated defensive lineman. In particular, on 3rd down passing situations, they moved Watt and Smith inside to tackle, and put linebackers Connor Barwin and Brooks Reed in the game as down defensive ends. The Texans defensive line was a key part of the defensive group that ranked 2nd in rushing yards allowed (96 per game), and 4th in offensive yards allowed per game (285). On the season (including the playoffs), the Texans gave up only two 100-yard rushers; Daniel Thomas rushed for 107 yards in week 2 and Ray Rice ran for 101 yards in week 6. One more stat, the Texans held the opponents leading rusher under 65 yards in 14 of their 18 games.
In particular rookie J.J. Watt and veteran Antonio Smith caused problems for opposing offenses all year long with not only their play against the run, but they supplied more pass rush than was expected out of 3-4 ends. Smith had 6.5 sacks on his way to making his first Pro-Bowl team and JJ Watt had 5.5 sacks, a team high 7 tackles for loss, and 4 passes defensed in a what most consider a Pro-Bowl caliber season. Watt stepped up his game even further in the playoffs with 3.5 sacks in their two games and an amazing pick 6 touchdown against the Bengals.
Watt, Smith, and Cody seem pretty locked in as the starters (especially Watt and Smith), but there are still some things to watch for during camp. I'm most interested in seeing how rookie 4th round pick Jared Crick out of Nebraska performs. Crick played like a 1st round pick during his sophomore and junior seasons, but an injury last season caused his stock to drop and allowed the Texans to pick him up in what should be a huge steal. In Wade Philips scheme, I think you'll see Crick play some 3-4 end, some defensive tackle in four man fronts/nickel packages, and even nose tackle with this system not requiring 330+ lb monsters in the middle. Phillips runs a versatile defense and Crick's abilities fit in very well. Crick won't start right away, but with Smith on the wrong side of 30, I like his potential as a future starter. At Nebraska, Crick had 9.5 sacks in both his sophomore and junior seasons; I think he'll surprise us with his pass rushing ability even as a 3-4 end. He reminds me a lot of JJ Watt with his size, strength, and non-stop motor; really think getting him in the 4th round was a huge steal.
Another guy with a chance to steal a little playing time is Earl Mitchell. The former 3rd round pick out of Arizona has shown flashes of potential as a pass rusher, but was a little undersized and never seemed to put it all together. Now in his 3rd season (normally when players take their biggest leap), and with reportedly 21 extra pounds, he could take some playing time from Shaun Cody with a good camp.
Overall, with J.J. Watt taking the next step in his career, and a full off-season in Philips defense; I think this will once again be a very strong unit.