Top defensive prospects By Charles Robinson, Yahoo! Sports January 26, 2006 More NFL draft: Top offensive prospects MOBILE, Ala. – As strengths and weaknesses go, Mike Nolan and the San Francisco 49ers have at least something going for them. For a team that's in need of impact defensive players, Nolan and his staff will see a wealth of them in Saturday's Senior Bowl. As many as seven defensive players on the field Sunday could end up being first-round picks, and at least four of them are coming from the pivotal defensive end spot: Penn State's Tamba Hali, Boston College's Mathias Kiwanuka, Miami's Orien Harris and Louisville's Elvis Dumervil. "With the linebackers, it looks like it's going to be a good year for (defensive ends)," Nolan said. "It seems like we'll see all of them." Not quite. But it will be close. It will be a strong year for defensive ends at the top of the draft, not to mention linebackers – a position that should see six players selected in the first round this year. Not surprisingly, those spots dominate the top-10 defensive players in this season's draft – with three linebackers among the top five. Here's a preliminary look at the cream of the defensive crop heading into the February 23-26 combine: 1. A.J. Hawk, outside linebacker, Ohio State Clearly the top defensive player in the 2006 draft, Hawk is the cream of a relatively strong class of linebackers. There aren't a great deal of weaknesses in his game. He has enough size (6-foot-2, 242 pounds) to play on either the strong or weak side, and he has the toughness and leadership abilities to have an impact immediately. Hawk locates running backs with ease, can shed blockers and is more than capable in pass coverage. If anything, he's slightly too aggressive at times, a trait that could lead to him over-pursuing some plays. He's not as fast as Texas' Derrick Johnson, but his instincts are just as good. 2. Mario Williams, defensive end, North Carolina State In terms of size, Williams is the total package – 6-7, 287 pounds. He has long arms, good footwork and good speed. Some scouts think he could be a Julius Peppers type, pushing his weight to as much as 295 without losing any of his athleticism. Like Peppers when he came out of North Carolina, Williams is still slightly raw technique-wise. He's more of a pass rusher at this point than a complete defensive end, but the feeling is that he's going to round into a more balanced player. His height can be a concern sometimes, as tall defensive ends can have issues getting leverage, but it's not an overwhelming concern. A lot of people are interested in seeing how he times out in the predraft workouts, because nobody is really sure how fast he'll be. If Williams blows people away with his workout numbers at the combine (or pro day), he could supplant Hawk as the draft's top defensive prospect. 3. Haloti Ngata, defensive tackle, Oregon At 6-5 and 340, Ngata is massive and strong. He might be the early favorite to win the title for most bench presses at 225 pounds in the February combine. A lot of people see him as the perfect fit as a nose tackle in a 3-4 defense. Scouts say he has a good burst and is the kind of powerful player who pushes blockers into the backfield at first contact. His stats haven't been mind-boggling, but he could develop into a player who commands a double team and makes surrounding players better. He also consistently improved during his time at Oregon, really breaking through last season. One thing that comes up a lot, though, is the question about his intensity. He's not a foaming-at-the-mouth kind of player and can be soft-spoken – traits that can be misperceived as a lack of passion. It hasn't shown in his play, though. 4. Chad Greenway, outside linebacker, Iowa He's not huge, but he has the size to handle himself on the weak side in the NFL. Like Texas' Derrick Johnson last year, there are going to be a lot of questions about whether Greenway can shed blockers, or if he's more of an avoidance-and-pursuit guy. He made some nice plays in Senior Bowl practices and showed a willingness to jam up blockers in the hole to blow up running plays. He seemed to have a little bit of a nastiness to him, too. You could hear him on the field a lot. 5. DeMeco Ryans, outside linebacker, Alabama He showed some physical flaws at the Senior Bowl. One AFC scout termed his performance through Wednesday as "good, but not special." He arrived smaller than expected – standing a shade under 6-2 and weighing 229 pounds, which is about eight to 10 pounds lighter than in college. He won't be able to play at that weight at linebacker at the next level. Scouts would like to see him at no less than 235 at the combine, and then they will be paying very close attention to his speed. It's expected he will run around a 4.6-second 40-yard dash. If he's slower than that despite all the prep work for the combine, his stock could take a hit. 6. Jimmy Williams, cornerback, Virginia Tech Though he hasn't played the position in two years, Williams could end up being a safety, depending on what his speed really is. Some scouts expect he'll run in the 4.50- to 4.55-second range in the 40. If he's faster than that, he could turn into a top 10 to 12 pick and be the first cornerback selected. He has very good size (6-2, 210) and should showcase a good vertical at the combine. Even if he doesn't have blazing speed, he should still be a top-20 pick because of the flexibility he gives having played both safety and corner. He's similar that way to Michigan's Marlin Jackson, who was a safety and cornerback in college and excelled in both spots for the Colts as a rookie. 7. Michael Huff, cornerback/safety, Texas Like Williams, Huff is another guy who saw time at both safety and cornerback in college. He also has good size (6-1, 205), is very athletic and has good instincts. He gets a little too aggressive at times, though, and has earned the reputation of being a gambler. He can make huge game-changing plays, but he can also give up big gains in risk-taking mode. He's another guy who is expected to run in the 4.55 range in the 40 and, from the scouting buzz, is more likely to be a safety than Virginia Tech's Williams. 8. Tamba Hali, defensive end, Penn State Hali had a solid Senior Bowl practice week. North coaches remarked that he was very receptive to coaching and typically corrected technical mistakes quickly in drills. Though he doesn't have the tall build of Boston College's Mathias Kiwanuka, (Hali is about 3½ to four inches shorter), Hali's 265 pounds make him a tough assignment for tackles. He gets good, low leverage, and he used his arms well to disengage from blocks. He's not expected to have a great 40 time (likely in the 4.6 to 4.7 range), but his game is more about technical ability than speed. He's probably the most refined defensive end in the draft. 9. Ashton Youboty, cornerback, Ohio State Had he hung around another season, Youboty might have been the top corner in the 2007 draft. He has good size (6-1, 190) and very smooth coverage ability with a ton of room to grow with his technique. He doesn't have the polish of corners Jimmy Williams and Michael Huff. He will most likely run faster than both of those players and has shown a very good ability to break up passes, but he's simply not as refined and isn't seen as someone who could step in and start for a team as a rookie. He's more likely to spend a year in nickel packages, and then move to a No. 2 corner slot. If he doesn't have a good run of workouts leading to the draft, it's possible Youboty will slip to the late first round or even further. 10. Mathias Kiwanuka, defensive end, Boston College It wasn't a great week for Kiwanuka. He injured his shoulder on Wednesday and had a relatively mediocre performance up to that point (for someone expected to be a top prospect, that is). He showed up a little thicker than in college, but a few scouts commented they would still like to see him add another 10 to 20 pounds to his very lean body (6-5, 260). A lot of people noticed when he had a myriad of difficulties against Virginia's D'Brickashaw Ferguson in one-on-one passing drills – including one instance when Ferguson plowed Kiwanuka under. He has ideal size (with room to grow) and good range, but his performance this week raised a lot of questions about whether he's technically skilled enough to defeat stronger top-notch tackles. He came in rated the No. 2 defensive end but lost ground. He has his work cut out for him going into the combine. Charles Robinson is the national NFL writer for Yahoo! Sports. Send him a question or comment for potential use in a future column or webcast. Updated on Friday, Jan 27, 2006 4:20 pm EST Still would like to have this guy back there with Roy.