He isn’t David Copperfield or David Blaine or Criss Angel, for that matter.

Marvin Harrison Jr., however, has all sorts of secrets up his sleeves. The rookie wide receiver for the Arizona Cardinals is full of magical skills and in very short order, the No. 4 overall draft pick is going to have a chance to showcase it for the entire NFL to see.

Unless the Cardinals start off by prematurely stunting his growth.

This isn’t to say that they are, or they will, or they might — just that they could. And here’s why:

The 6-foot-4 superstar son of a Pro Football Hall of Fame father, longtime Indianapolis Colts receiver Marvin Sr., has a unique bag of tricks when it pertains to his array of precise release moves, including multiple jukes, and stutter-steps to get off the line of scrimmage against opposing cornerbacks.

It’s one of the reasons Harrison enjoyed back-to-back seasons of 1,200 receiving yards and 14 touchdown receptions at Ohio State. Those multiple and artful moves allow him to get open, catch the ball, and make plays. It’s exactly what Cardinals coach Jonathan Gannon and offensive coordinator Drew Petzing want him to do.

But they’re telling us that less is more, in Harrison’s case.

“He’s got four or five releases,” Gannon said back in June. “Here’s your three you need to really hone-in on. Sometimes less is more with that, you know? Throw your fastball, man. Eighty percent of the time, throw your fastball. These other two are changeups, but this works, do it.

“So, I think it’ll be just a constant growth and learning from his standpoint of, ‘What works? What do I need to do? What does the quarterback expect from me? Who I’m playing against?’ It’s about different ways to get open versus different body types — little quick guys, big, long guys — that all matters. That’s the one-on-one battle he’s going to go through week in and week out.”

So, shouldn’t it be: The more he can do, the better? Why put any restrictions on a generational talent like Harrison? Shouldn’t the Cardinals do everything they can to exploit all his traits to their advantage?

When the Cardinals reported to training camp, I wanted to circle back with Gannon and dive deeper into the subject.

“He’s just going to have to go through camp and find out what really works for him on certain things and that’s what I really meant by it,” Gannon explained. “It’s good to have different tools in your toolkit, but I think when I said and what I meant was, ‘OK, when your fastball works, eight out of 10 times throw your fastball.

“I kind of liken it to (pass) rushers. You watch great rushers and if they get double-digit sacks, 80 or 90% of their sacks are on their fastball. Then 20, 10% are on their changeup. So, you throw your fastball if it works and keep throwing it and make ’em hit it.”

Look, I get it. Gannon is a defensive-minded coach. But Maserati Marv isn’t a pass rusher. He’s a wide receiver, and if he finds an ideal chemistry with quarterback Kyler Murray, he stands more than a decent chance of winning Offensive Rookie of the Year honors.

Who knows just how good he can become? The guess here is that with the right offense, the right coaching, and quality play out of the quarterback position, Harrison could be a perennial All-Pro who threatens a lot of Larry Fitzgerald’s marks in the Cardinals’ record books.

Will making him stick with his “fastball” limit his potential? Remaining curious about this whole thing, it was time to check in with Petzing, the second-year OC, to gauge his opinion.

“I think it’s a balance,” he said when asked how many release moves the Cardinals want Harrison to use. “I think most good players are really good at something or really good at a small handful of things and you certainly are going to need pieces to compliment that. But I think as JG said, you don’t want to forget about what made you really dynamic or what makes you really difficult to cover.

“So, we are constantly going to work with him to find that balance, to say, ‘Hey, make sure you’re using your top skills, your top release, your top, top of the routes,’ but also understand that when people see that and you put it on tape, they’re going to have an answer and you need to make sure you’re building some type of compliment to that so you don’t become easy to defend.”

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Not many opponents could stifle Harrison over the past two years. Yes, it won’t be as easy in the NFL, where the defensive backs are stronger, faster, and equally elite. Harrison knows that, but Murray knows Harrison, and he fully expects the rookie to shine from the start.

“The natural ability. You just watch him. You can watch him and tell,” Murray said. “When a guy’s got it, he’s got it, and he definitely has it.”

When it comes to his array of moves off the line, Harrison said they will be deployed differently depending on the game plan and which specific defenders he will be playing against.

“I always have my base releases that I can always go to, that I feel comfortable with,” he said. “There’s not really a number to them. It’s kind of just out there feeling for it and then you have your counter moves off everything.”

As for being told to stick with his “fastball,” Harrison has his own take on the suggestion. And he used a baseball metaphor to explain how he feels about it.

“It’s similar to a pitcher,” he said. “You can’t just keep throwing the same pitch over and over. You’ve got to give them something to think about otherwise.”

In other words, you can’t just keep throwing your fastball. You’ve got to mix it up. Take it from Cardinals receiver Michael Wilson, who was so impressed with a particular release move Harrison used during an offseason practice that he made him explain it to him in detail.

“I was like, ‘OK, I’m going to try and do that,’ ” Wilson said. “That’s sort of a real-life example of how I’m so open to learning from what was the best wide receiver in college football and what I think will be one of the best receivers in the NFL.”

Is less really going to be more? Or is it the more, the merrier?

“I don’t think I’ve seen them all,” Cardinals cornerback Sean Murphy-Bunting said of Harrison’s release moves, “but I’m sure he’s got a lot more in his bag that he’s not trying to show right away.”

We’ll see if the Cardinals let him do it or not.

Reach McManaman at bob.mcmanaman@arizonarepublic. Follow him on X, formerly Twitter: @azbobbymac and listen to him live every Tuesday at 3:30 p.m. on Roc and Manuch on Fox Sports 910-AM.

This article originally appeared on Arizona Republic: Cardinals want Marvin Harrison Jr. to stick to his 'fastball.' Why?