New Eagles cornerback Ronald Darby is more than just a speedy cornerback.
It's just that his speed really stands out.
"It's crazy," said Eagles safety Terrence Brooks, who was teammates with Darby at Florida State. "The guy is so damn quick, it's crazy."
Complete coverage of the Philadelphia Eagles and their NFL rivals from NBC Sports Philadelphia.
Two years ago, when he was a second-round pick of the Bills, Darby ran a 4.38-second time in the 40-yard dash at the combine. It was the second-fastest time for a defensive back that year.
On Saturday afternoon, the day after the Eagles traded for him, the 23-year-old corner said he's even faster now.
So what would his 40 time be today?
"Right now in a 40?" he said. "I know for sure, low 4.3, high 4.2."
Darby, aside from excelling in football, was a track star in high school. He was a member of the USA medley relay team that won a gold medal in the 2011 World Youth Championships in France. Darby took bronze in the 200 meter race with a time of 21.08.
So Darby doesn't just have speed. He has world-class speed.
"That's the first thing you notice about him," said Ron Brooks, who was Darby's teammate in Buffalo in 2015. "He's a fast guy. He doesn't really get ran by on a lot of routes. He runs pretty much with the fastest receivers. He's going to be a good addition for the team."
Even if Darby does get beaten by receivers, he has the wheels to recover. And for the safeties on the team, they'll feel more comfortable trusting a corner with that recovery ability.
While Darby is known for his speed - and rightfully so - he made it a point on Saturday to make sure people know he's more than that.
"Everybody knows me for my speed," he said, "but I'm willing to come up and tackle and just play aggressive. Get to the ball, make plays."
In fact, it was actually Darby's physicality that Terrence Brooks brought up first when asked about his college teammate.
Brooks, who is known as a hard-hitter, said that physicality was something instilled in the secondary while both were Seminoles.
"The kid's physical," Brooks said. "He likes to play in the run, get down there and get nasty. He's tight in coverage, he doesn't shy away from contact."
As fast as Darby is on the field, he's going to need to be pretty quick off it. He doesn't have a long time to pick up a new defense.
He arrived to Philadelphia on Friday night after the trade and has less than a week before the Eagles' next game on Thursday. Darby walked out for practice but was unable to participate. (By the time practice started, in Buffalo Jordan Matthews had yet to take his physical, which was needed to complete the trade.)
If Darby is able to practice on Sunday, that would give him three days of practice and a walk-through before Thursday's game against his old team, the Bills. Head coach Doug Pederson said he's hoping to give Darby some reps, although they're taking it "day by day."
Pederson said with Darby's understanding of defense, it should take him just a couple of days to be ready to go, especially because things are simple right now without game-planning for specific offenses.
Even Darby admitted that as a cornerback it shouldn't be that hard to catch up.
"I mean, he's playing man (coverage)," said safety Jaylen Watkins, who was teammates with Darby briefly in Buffalo in 2015 and knows him from their days as rivals in college.
"We brought him over here to play man coverage. And everything else, we'll help him along the way. I think the biggest thing for us is finding man corners and he has that ability. He was born with it. At the end of the day, man is man and we'll teach you everything else."
The story with Darby is in 2015, his rookie season, he had a great year. He had 21 passes defensed, two interceptions and was named to the All-Rookie team.
He simply wasn't as good in 2016. Darby said he still made plays last season but didn't finish them as much as he needed to. That's what he needs to work on this season with the Eagles. When asked, Darby said he feels like he has something to prove to himself and fans.
One thing is for sure: the Eagles are going to need him this season. Aside from their obvious weakness at cornerback before the trade, the Eagles are in a division with receivers like Odell Beckham Jr., Dez Bryant and Terrelle Pryor. And it'll likely fall on Darby to shut them down.
"This division's got a lot of great receivers, but I feel as though I should do great," he said. "Just go out there and compete."
After Darby exited the NovaCare Complex in his new all-black Eagles sweatsuit and green bucket hat alongside Brooks, he walked over to injured second-round pick Sidney Jones and the two had a long chat. They eventually walked closer to the field and watched the beginning of practice together. There's a chance the two are the Eagles' starting cornerbacks in 2018.
The Eagles have some young talent at cornerback now. Jones and Rasul Douglas are 21. And with two years already under his belt, Darby is still just 23. He said it's "exciting" to hopefully be building something in Philadelphia.
"There's a lot of talent," Darby said. "The future is looking bright."