Khalil Mack possessed traits that enraptured NFL scouts.
Yeah, but could he fit into any defensive scheme?
Mack was a hellacious pass-rusher for the University at Buffalo, dominating the Mid-American Conference and amassing school records.
Yeah, but how would he stack up against pedigreed competition?
He would erupt from his stance, use uncanny leverage skills to manhandle blockers and chase down quarterbacks in a blur.
Yeah, but he was 20 pounds smaller and maybe an inch or two shorter than the NFL's pass-rusher prototype.
Mack was a blue-chip prospect entering the 2014 draft, but nits get picked and microscoped when scouts comb through a rookie's every facet.
Yes, there was excitement Mack could be an extraordinary NFL player. That speculation has been confirmed, and a lot of teams wish they would have foreseen all the possibilities.
Mack is back Sunday for his first game in Western New York since December 2013. His Oakland Raiders will play the Buffalo Bills at New Era Field.
He returns perhaps as the NFL's brightest defensive star. And if he isn't, then he's on a list with only one or two others.
"He's a disruptive player in the pass game and run game," Bills fullback Pat DiMarco said. "You've heard him referred to as a game-wrecker."
We certainly know that now. He has been a first-team All-Pro twice in his three seasons. For 2015, he became the first player in NFL history to be voted All-Pro at two positions — defensive end and linebacker — in the same season. He was 2016's Defensive Player of the Year.
Mack has been so obviously astounding it's easy to wonder why he wasn't a first overall draft choice.
In retrospect, he not only should have been the top selection, teams should have traded multiple picks to jockey to the front of the line.
"He's a freak show," Bills left guard Richie Incognito said. "He's awesome."
Yet teams missed, predictably. We constantly hear scouting is an inexact science, but that suggests being off by a millimeter, a kilogram, an ounce.
Often, though, evaluations get out of whack.
From Mack's draft class, the Houston Texans took South Carolina pass-rusher Jadeveon Clowney first. The St. Louis Rams drafted Auburn tackle Greg Robinson second. The Jacksonville Jaguars picked Central Florida quarterback Blake Bortles third.
With Mack still available, Bills General Manager Doug Whaley traded their 2015 first-round pick to move from the ninth slot up to the fourth.
Mack had played the five previous seasons across town. UB held its pro day for Mack and his fellow seniors at One Bills Drive.
"We kind of thought Khalil would be the direction the Bills were going to go," Robert Wimberly said. The former UB linebackers coach was the lone college recruiter to offer Mack a scholarship out of Fort Pierce, Fla.
"For whatever reason, the Bills chose to go in a different direction."
Buffalo took Clemson receiver Sammy Watkins. Oakland drafted Mack fifth.
Neither Whaley nor Watkins is with Buffalo anymore. Mack has started every game for Oakland, his 56th straight to come Sunday.
He already has 34.5 sacks, tied for seventh on the Raiders' all-time list. Assuming his usual production, by season's end Mack will rank fifth in Raiders history behind only Greg Townsend, Howie Long, Anthony Smith and Bill Pickel.
Mack through seven games this year has five sacks, six quarterback hits and 20 hurries.
"He's different than many high-caliber, first-round players because he plays hard every down," DiMarco said of Mack. "Some high draft picks take plays off because they're that talented.
"He's a guy that has more talent than everybody else, and he plays harder than everybody else. He's the whole package. He's just a stud."
How, then, did four GMs pass on Mack and umpteen other clubs fail to trade up for him?
The reasons are plentiful and reasonable.
"What's hard for anybody, whether it's personnel guys or fans, is to recreate all the variables that surround that player and each team's individual situation," said Jeffrey Foster, president of National Football Scouting Inc., which runs the NFL Scouting Combine.
"From an evaluation standpoint, we always look at what the player will be in two or three years. Your team is very different every three years. Well, the fans and the talking heads are only looking at today. They're not taking it back three years to when we were actually making the decisions."
In Buffalo's case, Whaley valued a need over the best available prospect, a common approach.
Whaley was hell-bent on making the 2013 first-round selection of quarterback EJ Manuel work and was eager to invest heavily in a receiver.
The Bills in 2013 also fielded what appeared to be a cemented defensive line, with edge rushers Mario Williams and Jerry Hughes and tackles Kyle Williams and Marcell Dareus. Just three years later, Mario Williams and Dareus aren't on the roster, and Kyle Williams could be playing his final season.
"Should they have taken Mack? Yes," said Buffalo native and former Chicago Bears college scouting director Greg Gabriel. "But they should have stayed where they were, and they would've had Odell Beckham or Mike Evans.
"Do you give up next year's first-round pick to move up and draft a wide receiver that isn't even the best wide receiver in that class?
"The trade was stupid."
The Bills dismissed Whaley in April and four months later traded Watkins and a sixth-round pick to the Los Angeles Rams for cornerback E.J. Gaines and a second-round pick.
"People in Buffalo got fired" for trading up to draft Watkins, Gabriel said. "If they don't make that trade, Doug Whaley probably is still there and Doug Marrone's still the head coach."
Houston's decision to take Clowney is understandable. He performed sensationally against premier competition in the Southeastern Conference. He was two inches and 15 pounds heavier than Mack.
St. Louis taking Robinson was regrettable. Left tackle is a critical position to fill, and there were three good candidates in the 2014 class. Texas A&M's Jake Matthews and Michigan's Taylor Lewan became franchise left tackles for the Atlanta Falcons and Tennessee Titans, respectively.
The Rams in June traded Robinson to the Detroit Lions for a sixth-round pick.
The Jaguars choosing Bortles third overall was logical. Passers are more vital than pass-rushers. Although Fresno State's Derek Carr has been the best quarterback of the 2014 class, the Jaguars evaluated Bortles to be the best, plus Bortles is starting for the AFC South contenders.
"If you miss on a player," Foster said, "that doesn't necessarily mean you made a mistake. There are a lot of story lines that go into that decision and then play out afterward."
The Amherst Annihilator
Mack set an NCAA record with 16 forced fumbles and tied a record with 75 tackles for losses. His 28.5 sacks broke the school record.
Those numbers, however, were posted at UB. Before Mack, the program didn't have anyone drafted higher than the third round. That happened in 1964.
"As scouts, we do make more mistakes at that smaller-school level," Foster said. "We judge those guys a little bit harder because, naturally, you have to. It's important to keep an open mind and do your best to judge them fairly."
From 2000 to 2015, the NFL drafted 73 MAC players.
Seven conferences had more draftees. The SEC led with 519, followed by the Atlantic Coast Conference with 449, the Big Ten with 418 and the Pac-12 with 381.
"The bias is he's not playing against the best competition every week," Gabriel said. "He's now entering a league where it's not like he's jumping one level; he's jumping two levels. He's jumping past the Power Five-conference level and into the NFL level.
"Is it fair? No. But it does come into play."
Eagles quarterback Carson Wentz, the NFL's reigning offensive player of the week, faced similar scrutiny last year when leaving Division I-AA North Dakota State.
The Los Angeles Rams went with Cal quarterback Jared Goff instead as the safer selection.
Gabriel recalled scouting Akron defensive end Jason Taylor in 1996. Taylor fell into the third round, where a future Hall of Famer fell into the Miami Dolphins' laps.
Taylor is 6-foot-6 and was 243 pounds at his combine. His was about 255 pounds in his prime.
Mack weighed 251 pounds at his combine, but he measured a half inch shorter than 6-3. Coaches prefer their edge rushers to have height for pass-blocking abilities.
"Mack looked the part as a Pro Bowl linebacker, but not as much a Pro Bowl defensive end because he lacked the length," said Dan Shonka, former Eagles scouting executive and general manager of independent scouting service Ourlads. "He showed versatility, but a true defensive end in the NFL should be 270 pounds, so he can take on blockers and stuff the run.
"Was he that pass-rusher you really wanted? If you wanted a defensive end, his size probably pushed him down a little bit for some teams. But his versatility should have moved him back up."
Those examining Mack were influenced further by his disappointing 40-yard dash time at the combine and his decision to withdraw from the Senior Bowl, a chance to gauge him against tougher competition than he faced in the MAC.
But scouts couldn't deny what they saw when blending what they witnessed of his size and skill at the combine.
Mack ran the short shuttle in a blistering 4.18 seconds, locked out 23 bench-press reps and went 40 inches in the vertical jump and 10 feet, 3 inches in the broad jump.
Ourlads rated Mack the third most-athletic prospect out of the 49 front-seven players invited to the combine.
He ran the 40-yard dash there in an ordinary 4.65 seconds, but he ran it in 4.53 seconds at UB's pro day.
What probably improved Mack's draft stock most was former UB coach Turner Gill's decision not to dress him as a true freshman.
Mack's arrival at UB in 2009 was a cosmic accident.
He played only his senior season at Westwood High in Fort Pierce, Fla., because of an injury. Westwood coach Waides Ashmon pitched Wimberly, then an assistant at Division I-AA Liberty University, on Mack and quarterback Isaac Virgin.
Wimberly brought both to Lynchburg, Va., for a campus visit. Mack committed a week later. No other college made him an offer. When Gill offered Wimberly a job on UB's coaching staff, he convinced Gill to take a flyer on Mack.
"The big debate was 'Do we play him or do we not play him?' " said Gill, who left UB for Kansas and now is at Liberty with Wimberly. "He would have played some as a freshman. He might not have started, but he had some things other people don't have."
Gill described Mack as being blessed with natural explosiveness from a cold start and absurd flexibility.
"Some people can bend," Gill said, "but not everybody can do it in one quick movement, and it was effortless."
A redshirt season eventually provided Mack a glorious opportunity to show what he can do against a Power Five program.
His senior season, UB opened against Ohio State. Mack posted nine tackles, 2.5 sacks and an interception return for a touchdown.
The film from that game soothed most doubts.
One of Mack's biggest fans is John Opfer, his former strength coach. Opfer admittedly is biased, but he possesses detailed knowledge of Mack's finer physical wherewithal.
"I believe in my heart we haven't seen the best version of him yet," said Opfer, owner of Proformance Sports Training in Amherst. "He's still developing. Khalil could go down as the best defensive player in NFL history if he stays healthy.
"The fine line is at 257, 258 pounds and a little more optimized coming off the corner with more acceleration -- which is already ridiculous -- and balance to make even crazier cuts and set up quarterbacks for sacks.
"There's a small window where we can see an even better Khalil."
Lawrence Taylor traits
Shonka belly-laughed when relaying a story from late NFL scouting executive George Boone, player personnel director for the St. Louis/Phoenix Cardinals and Indianapolis Colts.
Boone would make fun of himself for years earlier harboring reservations about a revolutionary player.
"He told me he looked at nine films on Lawrence Taylor," Shonka said, "and couldn't decide if he was a first-round draft choice."
Taylor was a first-ballot Hall of Famer, an eight-time All-Pro, 10-time Pro Bowler, two-time Super Bowl champion with the New York Giants, one of only two defensive players to win the Associated Press' MVP Award and the AP's Defensive Player of the Year as a rookie.
Gabriel was with the Giants from 1984 to 2001 and has those same Super Bowl rings.
Gabriel called Taylor "the most dominant player I have ever been around. He wrote the book on 3-4 outside linebacker play" and added Mack "reminds me a lot of Taylor."
Taylor, ground-breaking as he proved to be, wasn't the first pick of his draft, either. The New Orleans Saints took Heisman Trophy running back George Rogers, who led the NFL in rushing as a rookie but was on another team four years later.
"I look at some clips of Khalil's pass rushes," Gabriel said, "and there's a lot of Taylor to him.
"I'm not going to say he's as good as Taylor because Taylor's one of the best of all-time. Khalil's got to do it over a 10-year period. But just his strength, his movement skills ..."
Pro Football Focus graded Mack the NFL's best edge-rusher last season. The analytics lab's "pass rush productivity" metric weighs pressures (sacks, quarterback hits and hurries) divided by number of pass-rush snaps. Mack rated ahead of all 3-4 outside linebackers and 4-3 defensive ends.
Mack's 74 hurries led the NFL last year.
He most frequently rushes from the left side, putting pressure Sunday on Bills right tackle Jordan Mills. Mack is attacking from the left 75.5 percent of the time, way up from 62.9 percent a year ago.
But he has been more effective from the opposite side so far this season. He has 10 pressures on just 49 right-side snaps, but 12 pressures on 151 left-side snaps.
"We pretty much know where he's going to line up," Incognito said. "It's a matter of diagnosing where and sending a bunch of people his way."
Mack blows up run plays, too.
He leads all NFL edge-rushers with 25 solo tackles on run plays, 19 of which are "stops," a Pro Football Focus metric for tackles that prevent an offense from improving its down-and-distance situation.
His 44 run tackles last year were one behind Denver Broncos outside linebacker Von Miller for the NFL's most.
"It doesn't always hold true, but what I particularly liked was his nonstop motor," Shonka said. "He was relentless, his aggression in backside pursuit.
"He could chase a back down like a cheetah chasing a gazelle. He just ran them down."
Mack dropped into pass coverage an average of only 2.4 snaps a game last year, and it's a rarer occurrence so far this season. Through seven games, he has dropped into coverage nine times.
Buffalo is preparing for the best pass-rusher they've seen this year, and maybe a player who could become of the best ever to do it.
"We have his number circled several times in our playbooks," DiMarco said. "Hopefully, we can limit his plays.
"He's a dominant player, but we have good players as well. We're not fearing him, but we're going to need to know where he's at every play."
Story topics: Anthony Smith/ Bill Pickel/ Blake Bortles/ Carson Wentz/ Cordy Glenn/ Derek Carr/ doug marrone/ Doug Whaley/ E.J. Gaines/ ej manuel/ George Boone/ George Rogers/ Greg Gabriel/ Greg Robinson/ Greg Townsend/ Howie Long/ Jadeveon Clowney/ Jake Matthews/ Jared Goff/ Jason Taylor/ Jerry Hughes/ Khalil Mack/ Kyle Williams/ Lawrence Taylor/ Marcell Dareus/ Mario Williams/ Mike Evans/ Odell Beckham/ Pat DiMarco/ Richie Incognito/ Robert Wimberly/ Sammy Watkins/ Taylor Lewan/ Turner Gill/ Von Miller