"I was talking to Ron Roenicke, the bench coach of the Angels, [about Upton's arm] and Ronnie's a real hard grader, trust me," the Rays manager said. "Maybe one of the toughest I've ever been around. And he said, 'That's an 80 arm' -- 80 being the highest grade. Coming from Ron Roenicke, that is extremely high praise."
Last season, the Rays had another imposing arm in the outfield in Delmon Young, who played right field. Maddon said Upton has a stronger arm than Young and "always did."
Reporters threw out Vladimir Guerrero's name as someone who might have a stronger arm than Upton, and Maddon smiled: "Vlad used to be that. I don't think Vlad has that giddyup like B.J.'s got right now. You get over 30 and it's hard to maintain that."
Maddon was asked if Guerrero showing off his arm had taken its toll, and he shrugged his shoulders.
"I think anybody with a good arm likes to show it off," Maddon said. "Every guy you've ever seen with a good arm likes to show it off."
Upton conceded he does enjoy showing off his arm.
"But you have to be smart, man," Upton said. "You've got to save your bullets for when you need them. Obviously, some plays you're going to need it more than others."
There are two enjoyable facets of having a golden arm, one is actually throwing out a runner and the other is watching a runner hold up out of respect for your arm. Upton said he enjoys both equally.
"Throwing a guy out is fun, but to see a guy hold up because there is a chance he could be thrown out is big," Upton said.
In addition to Upton having a strong arm, Maddon said the Rays center fielder has learned to charge the ball well and get rid of it quickly.
"Even if you don't have the greatest arm in the world, when you charge the ball and get rid of it quickly, you will stop runners," Maddon said. "And you don't want to challenge runners into running. That's not the point.
"You don't want to try and show off your arm and say, 'Go ahead and run, I'm going to try and throw you out.' I would much prefer the way where you come after it quickly, get rid of it quickly and stop them. Don't even let them think they can. That is the right way to play the outfield. B.J.'s been doing a great job coming in on balls lately. I really like the way he's been charging the ball. He's getting rid of it on a low feed to the cutoff man. It's beautiful."
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.