EAST RUTHERFORD, N.J. -- One workout session this summer was all veteran cornerback Prince Amukamara needed to know the New York Giants had a real player in second-round wide receiver Sterling Shepard.

Amukamara, who signed with the Jacksonville Jaguars this past offseason, was in California when he went to work out with Odell Beckham Jr., his former teammate. Beckham had brought along some additional competition. Shepard was there for the test. He had become fast friends with Beckham, and accepted the invitation to come train and hang with his new teammates for a few days.

Amukamara, Beckham and Sheppard ran drills and did some one-on-ones. Amukamara knew what he was in for with Beckham, one of the NFL's top wide receivers. They had gone against each other at practice with the Giants each of the previous two years.

Beckham's ability and refinement was expected. It was what Shepard showed that blew Amukamara away.

Sterling Shepard makes up for his 5-foot-10 height with his athleticism and speed. Tom Pennington/Getty Images

"His confidence and raw skills … he's just confident in his ability that he's going to beat the man across from him," Amukamara said. "And he's very sudden at the line, meaning he's quick. He has a combination of [Victor] Cruz and Odell's skillset."

That's quite the compliment. Cruz and Beckham are Pro Bowl receivers. Together, they can pretty much do it all. Shepard is a rookie who just made his NFL debut after being drafted by the Giants 40th overall out of Oklahoma. He has impressed the coaching staff, front office, and his teammates with his attitude and ability. He's managed to remain humble.

"It's good to hear," Shepard said last week of the praise before scoring a touchdown in his NFL debut. "But I still got a lot of work to do in my eyes."

He can look back at one play in particular against the Cowboys. Shepard gave up early on a third-quarter route and didn't work back to the ball. It was intercepted and the Cowboys scored their only touchdown of the contest as a result.

But the Giants believe those types of plays are blips on the radar. They're the anomalies.

"He's not a guy that makes a bunch of mistakes," coach Ben McAdoo said sternly on Wednesday. "He'll make some mistakes like some young receivers do. He learns from them and he moves on. He can take hard coaching."

It may be a result of Shepard coming from a football family. His late father was a star at Oklahoma and played in the NFL. His uncle played in college. After Shepard's father died, coach Bob Stoops kept him close to the Sooners program.

Shepard was born to play football.

"This might sound strange: I've never, ever doubted that he would [make the NFL]," his mother Cheri said after he was drafted. "That's because when he was really small, his dad would say, 'Cheri, he's really athletic.' He would examine his form and be like, 'Look at his natural form when he throws a baseball.' Or, 'Look at the way he dribbles a basketball. He controls the basketball and dribbles real close to the ground. Look at the other little kid who bounces the ball high up and can't control the ball. [Sterling is] naturally athletic.'"

The innate ability is on display every day on the Giants practice field and in games. His 41-inch vertical leap (better than Beckham's) was evident when he jumped over the back of Cowboys cornerback Anthony Brown for his first career touchdown reception on Sunday.

The skillset that blew away Amukamara has caught just about everyone's eyes.

"I think he's going to be a phenomenal player," Beckham said. "Catches everything that comes his way. He'll go up and get it. Just looking forward to seeing him progress."

Shepard, 23, had three catches on four targets for 43 yards, including a key 20-yard grab on the game-winning drive in the fourth quarter of his NFL debut.

Finally, Beckham appears to have his sidekick after being on his own with Cruz injured most of the past two seasons. It was something their teammates knew before Shepard had played in his first NFL game.

"Just his confidence," cornerback Dominique Rodgers-Cromartie said of how he knew. "Usually you go against a rookie receiver they're always looking where they have to go. With him, you can just tell. With him, he comes up subtle -- cool, calm, and he gets in his route.

"And the way he runs his route you can tell if he's polished or not. Some receivers come into the league and show and tell their routes. He didn't come in and show and tell. That is how you know."

It wasn't only the cornerbacks who noticed. Those Shepard was playing alongside quickly became aware.

"Just how he attacked the ball and very few, none, hit the ground. He was catching everything. Sticky hands," wide receiver Tavarres King said of his first impression. "Right off the bat, I was like, 'This guy can catch.' Especially in the slot it gets on you pretty quick.

"And then it transitioned into route running and he could do that too. I knew from pretty early on he was real."

Shepard's size (5-foot-10, 194 pounds) is all that prevented him from being a higher draft pick. He has the speed, athleticism and college production to be a first-round pick. He carries himself as a seasoned professional.

This is among the first things the Giants coaching staff noticed. McAdoo raved about his commitment and demeanor earlier this summer. He likes the way Shepard goes about his business, especially for a young player new to the league and its ways.

It's no wonder Shepard was almost immediately playing with quarterback Eli Manning and the first-team offense this spring. He quickly earned Manning's trust and the expectations that have come along with his quick ascension.

"I'm just trying ... I want to just keep Shep under the radar," Beckham said during training camp. "Let him come out and have that phenomenal season that he's fully capable of having. Rookie of the year season, in my opinion. But keep that hush."

That may not be possible. Shepard scored an impressive touchdown in his NFL debut, and has a favorable matchup against a thin New Orleans Saints secondary on Sunday. He could be on the verge of becoming an impact player early in his rookie year. And there seems to be little doubt that Shepard will be a force alongside Beckham and Cruz.

As one NFC executive told me during the summer even before Shepard made his preseason debut, "He's going to be a really good player."

It's nothing new to those who received a close-up look this spring and summer. Amukamara and the Giants already knew. Now it's for the rest of the NFL to find out.