INDIANAPOLIS — Raiders coach Jon Gruden could not believe his eyes when Ole Miss wide receiver D.K. Metcalf walked into the room to interview with the Raiders this week at the NFL Scouting Combine.

Metcalf, a 6-foot-3, 228-pounder, looks more like a linebacker than a receiver, and made Gruden think back to an all-time great.

“He looked like Jim Brown,” Gruden said. “He’s the biggest wideout I’ve ever seen. You have to ask yourself, who is tackling this guy? So, if you’re a 175-pound corner and you’re tackling a 235-pound back or a 230-pound wideout or a tight end, you have to ask yourself, ‘Is this what I want to do?’ ”

Teams have been marveling at Metcalf all week here, just like people marveled at shirtless photos of him that circulated on social media.

In them, Metcalf looks like the Incredible Hulk. On Friday, Metcalf bench-pressed 225 pounds 27 times, more than many of the offensive linemen here.

Metcalf said he was surprised at how much the photos on social media blew up and said there was nothing deceptive about the way his body looked.

“There’s no Photoshop in that picture,” he said. “I know the work I put in, so I’m not worried about what other people are gonna say.”

When he went through the measurements this week, his body fat was a staggering 1.9 percent, which doctors will tell you is unheard of. Bodybuilders typically have a 3 or 4 percent body fat.

Metcalf credited the trainers he has worked with at EXOS, a human performance company, as he prepared for the combine. They had him on a strict diet that limited his carbohydrates. He said the hardest food for him to give up was strawberry milk.

All of the attention on Metcalf’s physique has not been positive. There are some who question if he is too big for a wide receiver. There are comparisons to David Boston, another bulked-up wide receiver who battled injuries for most of his NFL career.

“They haven’t met me yet,” Metcalf said of those who are doubting him. “They haven’t seen ‘too big’ in seeing what I can do on the field or as a 40 or bench 27 reps, they haven’t seen me yet, so you know they can compare me to other big receivers that have been unsuccessful but like I say, they haven’t seen D.K. Metcalf.”

Metcalf will run the 40-yard dash Saturday and teams will be watching closely to see if all that muscle can move quickly.

“I’m expecting to run fast tomorrow and shock a lot of people,” Metcalf said.

The NFL runs in Metcalf’s blood. His father, Terrence, was a third-round pick in 2002 of the Bears and he played on their offensive line for seven years.

He is cousins with Eric Metcalf, the former running back and kick returner for the Browns, and Eric’s father, Terry, who was a kick returner for the Cardinals.

At Mississippi, D.K. Metcalf had 26 catches for 569 yards and five touchdowns last year as a third-year sophomore.

His season was cut short by a neck injury that he said he is now fully healed from. Metcalf said he believes his size is an advantage over most cornerbacks and he will win the battles for the football.

Where most players describe toss-up passes as 50/50 balls, Metcalf had a different description.

“99-1 balls I call them,” he said. “The 1 percent I’m not coming down with it, it may be a bad ball by the quarterback.”

Metcalf believes he should be the first receiver taken in next month’s draft.

“I see myself as the best receiver in this draft, because I’m a competitor and I’m going to compete every day,” he said.

NFL teams must now decide whether there is more to Metcalf than an eye-popping physique.