Mark Zeigler: How fast are football players? DK Metcalf is about to find out.

©The San Diego Union-Tribune

SAN DIEGO — You've no doubt seen the video from last October. Arizona Cardinals cornerback Budda Baker intercepts a pass on the goal line and heads toward the opposite end zone, nothing but green artificial turf in front of him. Seattle Seahawks receiver DK Metcalf, a good 10 yards behind, takes off after him.

Catches him at the 8-yard line.

The next day, after the NFL gloated about Metcalf's "wheels," the USA Track and Field federation playfully tweeted that "NFL players are welcome to test their speed against real speed at the Olympic Trials."

To which Metcalf replied: "See you there."

"There" is Sunday at renovated Hilmer Lodge Stadium on the campus on Mt. San Antonio College in Walnut, for the USATF's Golden Games meet (1:30 p.m., NBC). Metcalf is scheduled to race the 100 meters against 16 others, including nine who have gone sub-10 seconds and seven who have competed in an Olympics or World Championships. The prelims are at 12:32 p.m., the final shortly after 2.

Metcalf has been conspicuously silent, reportedly training in Arizona and declining media requests. The only acknowledgement of his intentions is an eight-second video clip posted Monday on his Twitter account showing someone, presumably him, walking across a track and dropping a pair of racing spikes on the ground.

The guys he'll race Sunday have been — how shall we put this? — a little less subtle.

"I've been waiting on this day, for football players to come line up and see what world-class speed is," said Michael Rodgers, a two-time national champion in the 100 meters who has a personal best of 9.85 seconds. "Football players don't have any clue.

"They talk all this trash on Twitter. Shout out to DK for coming out to even experience it. I don't know what his take is on what his performance is really going to be. … I'm anxious to see how his so-called ESPN world-class speed matches up against the real world-class speed."

About two dozen Olympic sprinters have played in the NFL, most notably double gold medalist "Bullet" Bob Hayes with the Dallas Cowboys in the 1960s. And usually they go from track to the gridiron, not the other way around.

But rarely does the Venn diagram overlap, mano a mano, shoulder to shoulder, apples to apples, stopwatch to stopwatch. Rarely does the blur of blur come into focus.

The NFL calculated that Metcalf reached a top speed of 22.64 miles per hour in chasing down Baker on "Sunday Night Football" last October. Which seems fast until you realize Usain Bolt, in setting the world record of 9.58 seconds in 2009, was approaching 28 mph.

The asterisk: Metcalf was running on spongy artificial turf, in helmets and pads, weaving through traffic, in Week 7 of a grueling NFL season. Bolt was sprinting straight ahead on a urethane track, in shorts and racing spikes, on a balmy night, with a slight tailwind, with starting blocks to propel him forward, with workouts meticulously calibrating over the season for this very moment.

And Metcalf isn't running against the retired Bolt at Mt. SAC.

"If he wants to run, he can come run," said Noah Lyles, the top U.S. sprinter who is entered in the 200 on Sunday. "Be prepared to get your butt kicked. You're running against track and field runners. You're a respectable guy in your field, I understand that. You've got some speed and you want to try it out? Cool, fine, I've got no problems with that.

"I hope you've been training more than three months, because you're going to need it to go up against real people who do nothing but run for their life."

Adding to the intrigue is that Metcalf doesn't have a recorded 100-meter time. That's because he wasn't on the track team at Ole Miss. He was at Oxford High in Mississippi but specialized in the jumps and hurdles, although he was part of a 4x100-meter relay team that broke the state record.

The only thing we have is 4.33 seconds, Metcalf's time in the 40-yard dash at the 2019 NFL draft combine in Indianapolis, a record for players weighing at least 225 pounds (he had 228 on his 6-foot-4 frame with 1.9% body fat).

Now go to Bolt's world record at the 2009 worlds in Berlin, Germany. He went through 40 yards, or 36.576 meters, in … 4.34 seconds?

Not so fast.

The NFL uses a combination of hand and electronic timing at the combine. There is no starting gun like at a track meet, but a hand-timer presses start when the player first moves from a set position. A laser stops the clock when he crosses the line.

Hand timing results in faster times because of the delay between hearing the gun or seeing movement and hitting the stopwatch. In high school and many other track federations, the conversion for a hand-timed mark in the sprints is to round up to nearest tenth of a second and add .24 seconds (so a 10.13 becomes the electronic equivalent of 10.44).

A study of the NFL's hybrid system found the error was more like .175 seconds.

The NFL experimented with a fully automatic timing (FAT) system at the 2012 combine but never released the times, fearful, some club executives privately said, of the negative perception from the "slow" times. The league quickly returned to the hybrid system that produced times as low as 4.22, the record set by Washington receiver John Ross in 2017.

But Metcalf, Ross and the others at the combine get to start when they want. Track sprinters must react to a gun, typically costing them between .1 and .2 seconds because the electronic timing mechanism already triggered.

In Berlin, Bolt's reaction time (recorded by pads on the starting blocks) was .146 seconds. Subtract that, and you get 4.19. Add the .175 to Metcalf's 40 time to account for the NFL's hand-timed start, and you get 4.51.

And that's just for 40 yards. There's still another 69 to go in a 100-meter sprint, and most world-class sprinters don't reach top speed until 60 or 70 meters.

"I went and looked at his 40-yard (dash) at the combine, and he was kind of tapping out toward that line," Rodgers said of Metcalf. "Just adding 60, 70 meters onto the 40 yards that he was running is going to be kind of hard to deal with. And he has to do it twice, and that's if he gets through the first round.

"It's like, everybody's hyping him: 'Oh, DK is going to do this.' You have to get through both rounds, buddy. This isn't an all-comer's meet. This is an elite track meet. I hope the football (fans) understands this is our job, this is what we do every day. I hope he comes to play."

The rest of the track world is equally skeptical.

"Sprinters rightly feel disrespected," Michael Johnson, the former world-record holder at 200 and 400 meters, tweeted this week. "People don't understand their talent."

"All respect to (Metcalf) in the NFL," fellow Ole Miss alum and Olympic shot putter Raven Saunders tweeted, "but about to get dusted."

NBC announcer Ato Bolden, a four-time Olympic medalist from Trinidad and Tobago who has won the 100 at Mt. SAC, tweeted this after the video of Metcalf chasing Baker went viral: "10.4 second NFL guy runs down 10.6 second NFL guy. USA sports media: 'OMG, this is the most stunning display of speed! CERTAINLY he should be at the Olympic Trials!!!

"Speed is relative, folks. Stop it. Please."

The automatic qualifying standard for next month's trials in Eugene, Ore., is 10.05 seconds, something only eight Americans have done this year. A time of 10.20 gets you consideration for the remainder of the 32-man field; in 2016, 10.16 got in.

Rodgers put the over/under for Metcalf at 10.3, depending on the wind speed and direction. Some say they'd be impressed if he breaks 10.5.

Steve Magness, a track coach at Houston and author of several books about peak performance, predicted 10.6 or 10.7, reasoning "he'll be closer to the top female sprinters in the world than Olympic Trials qualifying (and) that's not meant to be a slight."

The Mt. SAC is loaded with sub-10 sprinters. The 36-year-old Rodgers has done it 46 times in his career. Isiah Young, a 2012 Olympic in the 200, has gone 9.92. Chris Belcher and Cravon Gillespie have gone 9.93. CJ Ujah, who ran the lead leg on Great Britain's victorious 4x100 relay team at the 2017 World Championships and was .01 seconds from reaching the 100 final at the 2016 Olympics, has gone 9.96. Kyree King clocked 9.97 last month at a meet in Florida.

"I don't know if DK has been practicing or what he's been doing," Rodgers said. "He could very well get to the warm-up area and see guys running and be like, 'Aw, I'm not doing this.' Until we get to Sunday and he's warmed up and he's in the blocks and they say (his) name, it's not real yet.

"He's on the start list, so he's got the first thing down. Now he just has to line up."