In 2017, John Ross ran the fastest 40-yard dash in NFL combine history. The wide receiver was viewed pre-combine as a top draft pick, his speed just one of many natural traits that had scouts salivating.

Ross was raw, however, and few teams had the University of Washington product projected to go in the first half of the first round. The Bengals selected him ninth overall and gambled that his 4.22-second motor would help offset whatever he lacked in experience.

But Ross’ rookie season was anything but a quick study, as it often is for receivers. He played in only three games, caught zero passes, and fumbled his only touch – on an end around.

Injuries, along with several outside variables, played a role in Ross’ early struggles. His last two seasons, while also plagued by various health setbacks, have shown promise and that he might end up being worth Cincinnati’s original investment. But his rookie year can be seen as a warning to teams that expect early-round receivers, especially outside burners, to contribute immediately.

Jalen Reagor doesn’t have Ross’ 40-yard-dash speed. But he’s explosive despite his time (4.47 seconds) at the combine. He’s still in the top third among receivers who ran since 1999. And in pads, Reagor was once clocked at 22.6 m.p.h. and was behind only Henry Ruggs III among drafted receivers in the average of his top five speeds.

The Eagles chose him in the first round for myriad reasons, but his speed was paramount in their decision-making. They viewed Reagor as a budding replacement for DeSean Jackson who could be mentored by one of the marquee big-play receivers of all time while also contributing.

The draft came amid a pandemic with NFL offseason workouts already shut down. Training camp was months away. But the coronavirus has continued to spread – at increasing rates – and the NFL has been forced to delay practices, cancel the preseason, and limit contact at team facilities.

Rookies will likely be the most affected by the restrictions. There are already numerous obstacles to playing right away, but this year will be unprecedented. The Eagles, though, might not have the luxury of allowing Reagor and other young receivers to watch and learn.

Jackson missed most of last season with a core muscle injury that eventually required surgery in November. He is 34, and one false move after his anti-Semitic social-media postings from being released. Alshon Jeffery is recovering from Lisfranc foot surgery in December and unlikely to be ready by the season opener. It’s fair to wonder whether the declining receiver will ever play for the Eagles again.

J.J. Arcega-Whiteside could have benefited from his first full offseason, but he remains a question mark after a disappointing rookie year. And veteran Marquis Goodwin announced Monday that he was opting out of the 2020 season because of COVID-19 concerns.

Greg Ward returns, and fifth- and sixth-round investments were made in John Hightower and Quez Watkins. But the Eagles, at least on paper, don’t have a receiver returning they can hang their hats on.

The offense has firepower elsewhere. Quarterback Carson Wentz and a formidable line are back. Zach Ertz and Dallas Goedert form perhaps the best 1-2 tight-end punch in the league. And running back Miles Sanders, after an impressive rookie campaign, should only improve.

But the lack of reliable outside speed left Wentz shorthanded and the offense reliant on plodding drives. Reagor – and Hightower and Watkins, who ran 4.43 and 4.35 40s, respectively – were acquired to address this deficiency. But it would be a stretch to expect any of them to immediately become a deep threat.

“That’s out of my hands. I just look at it as though things happen,” Reagor said Monday during a video conference. “People get hurt. Like Marquis, him opting out, those are things that can happen. So I just look it as just I’m going to take advantage of every opportunity I get.”

Reagor was always likely to get his fair share of snaps as a rookie. Ross is more the exception among first-round receivers. But few enter the professional ranks and make a splash, even with the benefit of sub-4.47 speed.

Of the 38 first-round receivers who ran that fast at the combine since 1999 – there have been prospects who opted not to run for various reasons – only two eclipsed 1,000 receiving yards as rookies: Odell Beckham Jr. (4.43 seconds) and Amari Cooper (4.42).

There were others who came close and would develop into perennial Pro Bowl players (see: Andre Johnson, 4.4; Calvin Johnson, 4.35; Julio Jones, 4.34), but they were often Top 10 picks who checked off size, speed, and ball-catching boxes.

Overall, the 38 receivers averaged 39.4 catches for 546.1 yards and 3.5 touchdowns. There were receivers who did little as rookies, such as Ross, and would improve in time; receivers who did little, such as Rashaun Woods (4.47), and flamed out fast; receivers who made healthy contributions, such as Jeremy Maclin (4.45), and would improve with each passing year; receivers who made healthy contributions, such as Anthony Gonzalez (4.44), and fell off a cliff in subsequent years.

Receiver has long been one of the toughest positions for rookies to adapt to in the NFL, although there are recent signs of improvement. The challenges are manifold: separating from press coverages, running disciplined routes, understanding offensive and defensive schemes, and gaining the trust of the quarterback, to name several.

Before Ross, Darrius Heyward-Bey was long considered the poster boy for placing too much emphasis on speed. He ran a 4.3 40, and the Raiders drafted him seventh overall. Heyward-Bey hung around for 10 seasons, but he never came close to fulfilling Oakland’s expenditure.

Teams often wait to gamble on speed guys, especially when they’re on the smaller side. Jackson was drafted in the second round – partly because of character concerns – but he exploded as a rookie, catching 62 passes for 912 yards in 2008.

Jackson’s 14.7-yard average that season was the second-lowest of his career, as then-coach Andy Reid found ways to get the ball into his hands on shorter routes. The Eagles are expected to utilize Reagor in the same manner, perhaps with jet sweeps and end-arounds.

Percy Harvin, another former first-round speedster (4.39), was a comp for Reagor in some of the Eagles’ draft write-ups. The versatile receiver logged touches through the air, on the ground, and as a returner.

Reagor might have better ball skills, though. Contested catches were a forte. Drops were also an issue. Still, the Eagles project the 5-foot-11, 196-pound receiver to be a consistent downfield threat, just as they once did Jackson.

Reagor has yet to work out with Jackson, but they have spoken.

“He just told me to go in with a mission in my mind,” Reagor said. “Go in with a big chip on my shoulder and know I can make a big contribution. It’s the reason why this organization drafted me. They believed in me. Don’t wait in the back. Just go ahead and step in now. Why wait?”

The Eagles might have no other choice.