"I call him, 'Franchise,'" Hudson said.
That's a fitting name for the young man who, in an organization loaded with prospects, is arguably the best of the bunch on this youth-infused team that has reached the National League Championship Series.
"He's poised like he's been here before," Hudson said. "He's going to be around for a long time. That's why you're going to be able to write his name in the record books with A-Rod and [Ken] Griffey [Jr.] when they were 19 or 20. He's got 10 tools."
There are really only five tools when it comes to baseball scouting parlance, but Hudson's point is that the five tools that Upton has are head and shoulders above most.
"He's got abilities that, bar none, are better than anyone I've ever seen," first baseman Conor Jackson said. "You forget the fact that he's 20 years old. You really do. He plays at another level. He's a grown man. There's no doubt about it."
And now that the D-backs have reached the NLCS, Upton has an October opportunity to show off his skills on a bigger stage and to a much broader audience.
Upton has played well so far in the postseason, going 3-for-6 with three walks and a pair of runs scored against the Cubs in the NLDS. If he continues with that type of performance on the bigger stage of the NLCS, he has a chance to join Andruw Jones and Miguel Cabrera as young players that announced their arrivals to the rest of the baseball world with big games during the postseason.
In 1996, when he was just 19, Jones hit .400 against the Yankees in the World Series. Cabrera, as a 20-year-old, hit .333 against the Cubs in the 2003 NLCS.
For now, just being on the stage is impressive enough for Upton.
"Being here is unbelievable," Upton said. "And being a part of this team which has done great things this year has been exciting for me."
Upton, selected with the No. 1 overall pick in the 2005 First-Year Player Draft, was a shortstop in high school. The D-backs converted him to center field the next spring and then to right field just prior to his August promotion to the big leagues.
D-backs players got their first look at him when the club invited Upton to Spring Training in 2006. His batting practice session drew rave reviews from the team's veterans.
And he still does to this day.
"For a 20-year-old to have a smooth swing like that, as effortless as he does, is amazing," outfielder Eric Byrnes said. "Those tools are going to get better. He's going to help us a lot more in the future, but he's the kind of guy that right now can go out and win a game for us all by himself."
That's why the D-backs elected to call him up in early August when Carlos Quentin went down with a hamstring injury. Upton had started the year at Class A Visalia, where he hit .341 in 32 games before being promoted to Double-A Mobile. With Mobile, Upton hit .309 with 17 doubles, four triples, 13 homers and 53 RBIs -- production the D-backs could no longer ignore.
"He passed every test we put in front of him," GM Josh Byrnes said.
Upton, who was 19 when he was first called up before turning 20 on Aug. 25, started off his big league career on fire, picking up multihit games Aug. 4, 5 and 7.
As expected, the league adjusted to him and his production fell off, but his confidence and comfort level never did thanks to the support he received from his teammates.
"The older guys told me to keep going and keep working hard," Upton said. "That's the biggest thing is just keep working hard and if you're good enough you'll come out of it.
"Keep your confidence and keep doing your work. Things fall in line if you're persistent about just working hard and making adjustments."
Being in the postseason has put him one up on his older brother, B.J. Upton. B.J., who is Justin's senior by three years, was drafted No. 2 overall by the Devil Rays in 2002 and has yet to appear in the postseason.
"He's made his comments, you've been up two months and you're already in the playoffs and I haven't sniffed it yet," Justin said with a smile. "But of course he's happy for me at the same time."
So are the D-backs veterans, who appreciate the fact that despite his skills, Upton shows a tremendous respect for the game.
"He's done a heckuva job," Hudson said. "I saw him in Spring Training a few times, so I knew what he could do. When you see him at the plate and the way he handles himself and his success, he's a great kid."
Said Byrnes: "The fact that he just fits in with us right now is amazing. He's played beyond his years, and that being said, he's still going to get better."