Scouts already know Maryland's mercurial wide receiver is lightning in a bottle, a touchdown waiting to happen, that he has tantalizing size, long arms and extraordinary athleticism.
They also know he is not a polished receiver, that he can be inconsistent catching the ball, and that he occasionally would disappear from the Terps' offense last season as a junior.
What they don't know - at least yet - is how his unique combination of skills will translate in the NFL. But early draft projections have him taken in the first round or, at worst, at the top of the second.
Mike Mayock, a draft analyst for the NFL Network, is among those intrigued with Heyward-Bey's talent. When he watches tapes, Mayock sees the explosiveness that generated eight plays of 50 or more yards in three seasons at Maryland.
"You look at his combination of height, weight and speed, and you want to believe he's a top 10 pick," Mayock said. "At other times, it doesn't look like he catches the ball naturally.
"I feel like I need to do more [film study] on him. Watching him makes me want to know more about him."
The combine is a giant job fair for college players heading into the draft April 25 and 26. More than 300 will audition at Lucas Oil Stadium over the next week with timed runs of the 40-yard dash, medical examinations and assorted team interviews.
At 6 feet 3 and 206 pounds, Heyward-Bey has already run a 4.23-second 40-yard dash (2006, at College Park). In 38 games for the Terps, he had 138 catches, averaging 15.1 yards. He had 34 catches of at least 20 yards.
Coach Ralph Friedgen gave Heyward-Bey his blessing in early January when the soon-to-be 22-year-old decided to forgo his senior year at Maryland for the NFL.
"If he runs a slow time [at Indianapolis], he'll still be faster than most of the guys running," Friedgen said. "He never ran slower than 4.2 for me. And it doesn't look like he's running [hard]."
Heyward-Bey was a world-class sprinter at McDonogh, where he ran track, played basketball and debuted in football as a freshman. In fact, football was the only sport he didn't play growing up in Silver Spring, where he was a basketball prodigy of some renown.
But Dom D'Amico, McDonogh's football coach, could see the long-term potential in Heyward-Bey, even if he was uncomfortable in pads at first.
"He was as raw as you could get," D'Amico said. "But you always saw something special in him. ... His speed is NFL-caliber. His demeanor and how hard he works, those are the things that make you want to help him develop. You can't get a kid with better character."
Heyward-Bey's speed, if not his ultimate career direction, was evident from the beginning. By the end of his junior year at McDonogh, he decided football was his destination, even though he was a first-team All-American in track in the indoor 60 meters.
"Looking at the facts, I probably should've gone to [college] for track," he said. "But I'm one of those guys who is very confident in himself. I knew in any situation I would be in, I was going to work hard to become the best."
He chose Maryland and football over LSU, track and the Olympics. Redshirted his freshman year, he served notice he was a player to watch in 2006 when he caught touchdown passes of 96 and 65 yards in a 14-13 victory over Miami.
What followed the next two years was a montage of big plays. As a sophomore in 2007, he had catches of 63 and 47 yards, runs of 54 and 37. As a junior, he had three receptions of 60 yards or more. And he gained 76 yards on an end-around at Clemson to inspire a Maryland upset.
But in the same game at Clemson, he was shut out as a receiver. A week later, the same thing. He was less consistent as a junior than he had been as a sophomore, partly because he was double-teamed regularly.
Mel Kiper Jr., an ESPN draft analyst and a Baltimore native, said the Terps "didn't make a concerted effort to get him the ball enough. He's got to get it six to eight times a game."
Friedgen said defenses forced the Terps away from Heyward-Bey.
"If I was coaching against Darrius, I'd make them throw the ball somewhere else," he said. "What do you do? Try to find a way to force the ball into him? Throw incomplete, then you're punting."
Still, when told of Mayock's assertion that Heyward-Bey did not catch the ball naturally, Friedgen said: "His technique has got to be better. Darrius knows that."
Toward that end, Heyward-Bey spent the past month in Phoenix at a training center called Athletes' Performance. There, he went through two workouts a day, running, lifting weights, doing the agility drills that will be timed at the combine.
He got on the field three times a week to catch passes from Georgia's Matthew Stafford, the likely No. 1 pick in the draft, and Kansas State's Josh Freeman. They are all in the stable of super-agent Tom Condon of Creative Artists Agency, which has represented the NFL's top pick in four of the past five drafts.
Ben Dogra, who helps represent Heyward-Bey at CAA, knows there are players coming out with better statistics. But he doesn't think anyone is coming out with better potential.
"He's a young player," Dogra said. "They'll have to project him. You're not going to take him in the first round based on pure numbers.
"His [college] production is a function of the offense, a function of him developing. He started football at a later age. He's still learning it. In two or three years, with better coaching, nobody knows how good he can be."
ABOUT THIS SERIES
He's 6 feet 3 and weighs 206 pounds. He runs faster than most people on the planet. He's the big-play wide receiver many NFL teams covet, and he could be chosen in the first round of the NFL draft. We begin a series of occasional articles looking at Maryland's Darrius Heyward-Bey as he prepares for the draft at the end of April. Today: Making sure he's ready for the NFL scouting combine.